February 2004

Gas

-Surface

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Editor - Isabel Nieto. University of Essen, Fachbereich Chemie, D-45117 Essen, Germany. Tel: +49 (0)201 1833056; FAX: +49(0)201 1833228. Email: Isabel.Nieto@Uni-Essen.de. Web page containing announcements and other information: http://www.pchem.uni-essen.de/gsd/

Issue Number 38

Editors Note

The first issue of the Gas-Surface News this year contains aresearch report on “

128

Xe NMR on single crystal surfaces”written by Heinz Jänsch and his colleagues from the physicsdepartment and the center for material science at thePhilipps-Universität in Marburg, Germany. We hope youenjoy reading about this new technique in Surface Science.

The advertisements of interesting open PhD and post doc-toral positions this time come from Germany, France, Eng-land, Ireland and the Netherlands. As usual we included theannouncements of forthcoming conferences you may beinterested to attend. This time they take place all overEurope as well as in the USA and in Venezuela.

We wish to get the next issue ready by the beginning of nextsummer. In between please feel free to send us anyannouncements you want to make as we will circulate themto the gas-surface mailing list. Please also get in touch if youwish to volunteer for the next research report.

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2 Research Report - “

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Xe NMR on Single Crystal Surfaces” by Heinz J. Jänsch, Philipps-Universität, Marburg

8 Papers for Publication

9 Conference Announcements and Job Vacancies

18 Diary Page

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Gas-Surface News

Research Report129XE NMR ON SINGLE CRYSTAL SURFACES

H. J. Jänsch, P. Gerhard, M. Koch and D. FickPhilipps-Universität, Fachbereich Physik und Zentrum für Materialwissenschaften,

D-35032 Marburg, GermanyCorresponding author: heinz.jaensch@physik.uni-marburg.de

http://www.physik.uni-marburg.de/surf

Nuclear magnetic resonance (NMR) is extremely successful in materials research, biology and medicine. Here we demon-strate that single crystal surfaces are in the reach of this most powerful technique. Necessary sensitivity gains of 105 areaccomplished by applying laser optical pumping to produce highly polarized 129Xe. Chemical shift measurements of 129Xeadsorbed on CO/Ir(111) and CH3C/Ir(111) reveal substantial shift differences thus demonstrating the usefulness of xenonas a local probe. The 129Xe shift on the bare metal is very large and shows the Fermi contact interaction of the xenon andthe metallic electrons (Knight shift). Despite the inherently low sensitivity of NMR techniques, they can be applied now to129Xe adsorbates that probe single crystal surfaces.

I. Introduction

Since its invention in the mid 40’s [1, 2] nuclearmagnetic resonance (NMR) has been among themost successful analytical techniques available. In1961 Abragam writes in his seminal book The Princi-ples of Nuclear Magnetism that NMR is capable ofmeasuring the finer properties of matter, they maybe structural, geometric, electronic or of dynamicnature [3]. He was more right then he might havedreamt himself. Fig. 1 shows the abundance of

NMR literature in physics alone. NMR contributesslightly less then 1% of all Physics Abstracts cita-tions over a span of 40 years.The signal observed in NMR is the response of theensemble of nuclear moments to an external excita-tion. This excitation or disturbance may be a conti-nuous or pulsed (typically π/2 or 90°) radiofrequency (rf) irradiation. On equivalent sites themoments answer synchronously which means theyperform oscillatory motions in phase. The momentdensity (magnetization) creates an albeit small butmacroscopic external field. This field must bedetected in NMR usually by induction as it is alsothe case in the current experiment. In their dynamicresponse the nuclei oscillate with a frequency pro-portional to the local field. This is in general differentfrom the external field B0. A bare nucleus would res-onate at γbare

. B0, with γbare being the gyromagnetic

ratio of the bare nucleus in question. The effect ofthe electrons is one of shielding, the local field beingin general smaller than B0. A bare nucleus is hardlyavailable for reference in most laboratories. There-fore, one uses practical reference substances forwhich ωo = γ .B0 (the γ is slightly different from γbare).Chemical differences are now measured in a localfield as differences from the reference substance

ω = γ . (B0 + B loc) = γ . B0( 1 + σ).

σ is called the chemical shift (a tensor in general). Itis independent of B0 and measured in units of 10-6 orppm. For 129Xe the low pressure gas serves as refer-ence substance (see Fig. 3). Its gyromagnetic ratio isγ/π = -11.8604MHz/T, which gives us a resonance

Figure 1: Frequency of NMR citations in the physics lit-erature. Given is the number of all citations, the numberof NMR related entries and the ratio. The latter levels offat about 0.8%. Dips occur at 'spin offs' like the discoveryof the chemical shift through chemists as a powerful ana-lytical tool. Nobel prizes were given in the field of NMRto: F. Bloch and E. M. Purcell (1952, physics), R. R.Ernst (1991, chemistry), K. Wüthrich (2002, chemistry),P. C. Lauterbur and P. Mansfield (2003, medicine).

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frequency of ν = 23.277MHz at 1.963T. For xenon σis (almost exclusively) positive which means higherresonance frequencies when compared to the gasreference line. For 129Xe the range of the chemicalshift is 0-350 ppm in the physisorption regime andup to 5000ppm in chemical compounds like XeF2[4].After a pulse excitation the induction signal is meas-ured free of further disturbances and is called freeinduction decay (FID) signal. The coherence of thenuclear response decays in the time T*2. This iscaused by spin-spin relaxation (T2) and dephasingdue to local inhomogeneities. The latter effect issmall in our setup so that T2 ≈ T*2 = 0.5 - 1ms. Themeasured FID signal must be Fourier transformedto obtain spectra (Figs. 3, 4, 7). The local differencesare site/molecule/environment specific and are thebasis of observing NMR spectra. In all its glory NMR has an enormous drawback.The sensitivity is inherently low. In very lucky cases6 . 1016 atoms are enough [5] for solid state NMR, butmore often 1018 or 1019 nuclei at equivalent sites arenecessary. In bulk materials this is usually no prob-lem. At 1015 sites/cm2 for a typical surface the nec-essary number corresponds to an area of 1m2. NMRinvestigations of large surface area materials can beperformed without a problem. Single crystal sur-faces of 1cm diameter are out of reach. Drasticallyincreased sensitivity is necessary. The magnetization observed in an FID signal of aconventional NMR experiment comes from theBoltzmann polarization Pz present at equilibriumwhen a nuclear ensemble is placed in a magneticfield B0 (z-direction) at a temperature T:

Pz = 5 . 10-6 for xenon at 100K and our 2 T B0-field. Again of 5 orders of magnitude in polarization andtherefore in signal is possible if one achieves Pz ≈ 1.Using laser optical pumping we do achieve Pz = 0.4 -0.8 on a regular basis [6, 7]. This is done by irradiat-ing a xenon-rubidium-nitrogen mixture with reso-nant circularly polarized light. This induces highelectron polarization in the very small Rb fraction ofthe mixture. Spin exchange in collisions of Rb with129Xe transfers the polarization to the xenon nuclei.Within less then a minute the 129Xe polarizationreaches a level of up to 0.8 [6, 7]. The rubidium andnitrogen gas can be separated without loss of polari-zation. Isotopically enriched xenon gas is used with71% of 129Xe and less than 1% of 131Xe (Urenco). The

optical pumping technique is well established innuclear and atomic physics. In NMR Xe withdynamically increased nuclear polarization hasbeen used to study small areas or diluted systems aswell as in imaging [8]. The technique enables us tostudy single crystal surfaces.The aim of our research is to harvest the treasure ofmethods available in conventional NMR for singlecrystal surface science studies. In order to study sur-faces relevant and comparable to results in the field,it is necessary to combine NMR with analytical toolsalready well established in surface science.What we show here is that an ultra high vacuumsurface science machine can be successfully com-bined with NMR and optical pumping.

II. Experimental

An ultra high vacuum (UHV) chamber is connectedto an NMR setup and to an optical pumping system[6, 9-11]. The base pressure of the UHV system is5 .10-10 mbar. The chamber contains the crystal, itssupport structure for heating, cooling and position-ing, a sputter gun, a quadrupole mass spectrometer(QMS) and a gas handling manifold. Cleaning of thecrystal is achieved by argon ion sputtering and/oroxygen treatment before annealing at 1150K. Thetemperature is measured by a chromel/constantan(type E) thermocouple. The 75µm thin wires arespot welded to the backside of the crystal. Below≈80K both wire materials become ferromagnetic.Therefore thin wires are mandatory in order to keep

P

k Tz = 12

hω

B

Figure 2: Temperature programmed desorption (TPD)spectra. At 58K the physisorbed multilayer xenon des-orption peak is visible. On CO/Ir(111) a monolayer peakis visible at 64K. On the clean metal the typical monol-ayer feature is visible at 92K.

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magnetic distortions below our detection limit. TheNMR spectrometer is essentially home built andconsists of a single channel irradiation and detec-tion system. The electromagnet produces a B-fieldof 1.96 T with an inhomogeneity of less than ±5µTacross the crystal. The stability during a day isabout ±3 µT.The laser polarized xenon is produced in a setup afew meters away from the NMR spectrometer. It istransfered from the optical pumping to the UHV-NMR-setup through a 5m long tube, made fromPTFA a teflon variant. The xenon is stored in frozenform in a reservoir and dosed onto the crystal byusing its own vapor pressure. Slow dose rates of 4 to40 monolayers per second (ML/s) are achieved byleaving the reservoir at 77 K or 87K (boiling pointsof liquid nitrogen and argon). Removing the coolantresults in a burst of xenon gas for a few secondswhich builds a film of about 1000 to 2000 monolay-ers thickness when the crystal is well below 60 K.The NMR experiments on the bare metal surface orthe molecularly covered one have to be repeatedmany times to obtain a large enough signal to noiseratio. To acquire hundreds of spectra the xenon isdosed continuously so that at an appropriate sub-strate temperature the xenon mean residence time isbetween 0.1 and 10s approximately. Thermally pro-grammed desorption (TPD) spectra are measured toestablish the temperature range where this occurs,i.e. ~ typically where the monolayer desorptionpeaks are. Fig. 2 shows TPD spectra of xenon des-orbing from Ir(111) and CO/Ir(111) [11].

III. Results and discussion

III.1 Bulk surface resonance

As mentioned above, the chemical shift is usuallymeasured as a shift with respect to a reference sub-stance. Those are in our case the low pressure gas(σ=0ppm) and the resonance line typical of xenonin the bulk. Fig. 3 shows the gas and solid line in thelower trace (a) [11]. The upper one shows spectraobtained during bulk growth when the iridium at61 K is dosed with 40 ML/s. The bulk like line at300-310 ppm is accompanied by a line at 209 ppmonly observed when the bulk is being built duringthe xenon dose. Also spectra have to be taken at ahigh enough rate so that the surface peak (alwaysnew and highly polarized xenon) is emphasized.The line position of the surface peak can be under-stood semi quantitatively [7].

III.2 Xe on CO/Ir(111)

The TPD monolayer peak at 64 K (Fig. 2) shows thatin the range from 60 to 70 K one can expect themean residence time of Xe on CO/Ir(111) to be inthe vicinity of 1 s. Therefore, NMR spectra weremeasured in that temperature interval. The xenonflux was reduced to 4 ML/s, so that the bulk onlycondenses below 60 K. The insert in Fig. 4 shows aresonance line obtained at 61 K. It is a sharp (∆ν = 5ppm) line shifted to σ = 153 ppm. The main part ofFig. 4 shows the temperature dependence of thispeak. The low temperature part shows the line posi-tions typical of the bulk and surface of the bulk as inFig. 3. We find a strictly linear behavior from 60 to67 K with a rather strong temperature dependentchemical shift of -3.3 ppm/K. Using a kinetic rateequation model that can be calibrated by simulatingthe TPD spectra one finds that the xenon adsorbs in2 layers. The first one mostly full and the secondone varying from full to empty within the tempera-ture range. The modeling still needs much refine-ment as only first order desorption was simulatedand islanding not taken into account properly. Thefact that only one sharp line is visible in the NMR

Figure 3: 129Xe NMR absorption spectra. Frequency scaleon the bottom, ppm scale on top of the figure. The fre-quency scale shows differences towards a local electronicoscillator and its zero is chosen for convenience in theNMR spectrometer setup. The position of the gas line isset to 0 ppm. (a) The gas and bulk xenon lines. (b) Xebulk (≈ 310 ppm) and surface peak (SB1) at 209 ppmshift. At 61 K the bulk can only grow under high xenonflux conditions (40 ML/s).

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spectrum shows that fast exchange between all sitesaccessible occurs on the relevant (NMR) timescaleof about 1 to 0.1ms. This is not too surprising sincethe surface is at or above the TPD desorption tem-perature. Therefore, diffusion and site exchangeshould be very fast.

III.3 Residence time of Xe on CO/Ir(111)

The exchange rate of Xe on the surface can be meas-ured with NMR techniques. This is done by aninversion recovery experiment as shown in Fig. 5. Ina first step the polarization of the adsorbed 129Xe isinverted by a 180° pulse. Then after a waitingperiod τ a normal 90° pulse, a read out pulse, isapplied. If the waiting period is short then themeasured absorption line has the opposite signfrom 'normal'. After a long time the situation is notdifferent from not applying the 180° pulse at allsince the sample is dosed continuously. The signalbehaves like A(t) = A0(1-2exp(-t/τex)) and the meanexchange time τex can be extracted. This is also themean residence time τres = τex, when all xenon atomsadsorbed take part in the exchange process. Thisshould be the case at or above the TPD desorptiontemperature since diffusion must be expected to bevery fast. Fig. 6 shows the result of such an exchange ratemeasurement. The data follows the described

behavior and the extracted times are τres = 240ms at63.4K and 64.4K. At 61.2K the curve showsτres=565ms but does not follow the expected behav-ior too closely. The error in the fit parameters is

56 58 60 62 64 66

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7

8

9

10

Xe-Film Xe/Xemult/Ir(111) Xe/CO/Ir(111)

NM

Rfr

eque

ncy

[kH

z]

-3.3 ppm/K

T [K]

150

200

250

300

shift

[ppm

]

0

0ppm 200 400 600 800

5 10 15 20 25

-2

0

2

4

6

8

ampl

itude

[a.u

.]

frequency [kHz]

Figure 4: The main body of the figure shows the line posi-tion of this resonance as a function of temperature. Atlow temperatures the bulk and its surface line appear.Above 60K only a single narrow resonance (4-6ppm) isvisible indicative of homogeneous conditions. The insertshows the NMR line of 129Xe on CO/Ir(111) at 61K. Allexperiments were performed with 4 ML/s xenon flux.

-cP0

180° 90°

P0

Pz(τ)

Pz

t

t

τ

Figure 5: Schematic diagram of an inversion recoveryexperiment to measure the exchange rate of the adsorbedxenon with gas phase xenon. First a pulse inverts thepolarization of the adsorbed atoms. Then after a time τ theFID is measured. The FID is proportional to the polariza-tion of the adsorbate ensemble at that time. The waitingtime dependence of the FID amplitude therefore measuresthe exchange rate. The duration of the rf-pulses is around15 µs and of the FID 5 ms. The waiting time is in the sec-ond range.

0 250 500 750 1000 1250-1,5

-1,0

-0,5

0,0

0,5

1,0

Pz/P

0

[ms]

T=61.2K

T=63.4K

T=64.4K

Figure 6: 129Xe NMR results of an inversion recoveryexperiment (under constant xenon flux). The signalamplitude normalized to the one without the inversionpulse Pz/P0 is shown as a function of the waiting time t.The lines show fits with the function A(1-2exp(-t/τex))and the mean exchange time tex is extracted. 240ms arefound for 63.4K and 64.4K and 565 ms at 61.2K.

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about 10%. The astonishing facts are: the times areso similar, they are short, they are close to theinverse of the adsorption rate (4ML/s in theseexperiments). From the TPD analysis one expects afactor of 2 to 3 in the residence times for a tempera-ture change of 1K. Within the 3K range of the exper-iment an order of magnitude change in τres isexpected but not seen. If one looks at Fig. 2 the TPDpeak at 64K has a width of about 5 K and at a heat-ing rate of 4K/s this means the residence time is atleast 1 s at 64 K - considerably longer at 63 or 61K. To understand all of the observations one must rea-lize that the TPD only looks at the last layer withouta second layer being present (at 64K). The experi-ment here is done in a dynamic equilibrium situa-tion at constant temperature. Here the second layeris partially filled. The adsorption flux is 4 ML/s andin equilibrium the same amount must desorb. Theresidence time in the second layer must be shorterthan 0.25 s, otherwise the layer would be filled andbulk growth would occur. The latter is not the casesince the NMR spectra show a single sharp line faraway from the bulk line (Fig. 4). The occupancy ofthe first and second layer adjusts itself so that thedesorption is again 4ML/s. In the first layer the Xeatoms have 6 neighbours or only little less on aver-age. In the second layer is probably less. This resultsin substantial chemical shift differences betweenfirst and second layer. Roughly one expects 25 ppmshifts per neighbouring Xe atom thus giving300ppm in the bulk and around 150ppm in a fullmonolayer. A 50ppm difference between first andsecond layer would result in two lines in the spec-trum split by 1kHz. This is not seen experimentally.The observation of a single sharp line (width of 100to 150Hz) shows that fast exchange of the layersmust be present. The phenomenon of merging reso-nance lined through fast exchange is calledmotional narrowing. The rate of exchange has to beat least an order of magnitude above the frequencydifferences. The observed residence times at 64.4Kand 63.4 K of 0.24 s means within our simple modelthat the surface has a total coverage of 1ML. Thedistribution between first and second layer may bedifferent. The longer time at 61.2K means about2ML coverage. The exchange rates between firstand second layer must be in excess of 10 kHz. Theanalysis is crude, no question. A detailed kineticMonte Carlo simulation is called for in addition to athen possible chemical shift calculation.

III.4 Xe on Ir(111)

The experiment that might come to ones mind atfirst is the NMR of 129Xe on the bare metal. Expecta-tions were that this may not be possible due to avery short T1 time [10, 12]. After the successfulexperiments on the molecularly covered substratethe experiments on the metal itself were performednevertheless. Fig. 7 shows the measured NMR line.Its chemical shift is much above the physisorptionrange indicated by the gas and bulk line in the fig-ure. The iridium metal is paramagnetic whichmeans that the electrons at the Fermi level are notpopulating spin up and spin down states equally. Athorough discussion shows that the large observedshift is due to Fermi contact interaction between thexenon nuclear moments and the electronic momentsof the conduction electrons at the Fermi level [14].The shift is known as Knight shift and typical formetals. Chemically bound adsorbates have beenknown to show Knight shifts [5, 13] but for phy-sisorbed species the situation is not so clear cut [12].The shift shown does depend strongly on the angleof the surface orientation with respect to the exter-nal field (shift anisotropy). The size of the shift andits anisotropy can only be understood when contactinteraction is the dominant interaction mechanism[7, 14].

Figure 7: 129Xe resonance line of Xe directly adsorbed tothe metallic Ir(111) surface. The temperature is such thatthe first monolayer is partially filled, the second one notat all. A narrow line is observed that is shifted far abovethe physisorption regime. The paramagnetism of themetal electrons lead to this bahavior through Fermi con-tact interaction and Knight shift.

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IV. Conclusion

This short contribution was intended to show anew/old tool that has been devised for applicationin surface science. In the past, NMR experiments onsingle crystal surfaces have been conducted alreadywith alkali metal adsorbates like Li or Na [15-19]. Inorder to perform those highly specialized experi-ments tools completely uncommon to NMR had tobe developed. Here in contrast the experiments maybe uncommon to surface scientists especially thosestudying single crystal surfaces, but the metho-dology and equipment is very close to conventionalNMR. In principal all components are commerciallyavailable as in Xe-polarizers, NMR magnets andelectronics. Nevertheless, much development hasstill to come. Xenon is an interesting probe to studysurfaces but certainly one would hope to investigate1H, 13C or 29Si directly. In double resonance experi-ments it is possible to transfer polarization from onenuclear species to another. In this manner sub-stances other then xenon may be accessible to NMRon single crystal surfaces in the future.

Acknowledgment: The authors wish to thank theDeutsche Forschungsgemeinschaft (DFG), Bonn, forthe financial support.

[1] E. M. Purcell, H. C. Torrey, R. V. Pound, Phys. Rev. 69 , 37 (1946)

[2] F. Bloch, W. W. Hansen, M. Packard, Phys. Rev. 70, 474 (1946)

[3] A. Abragam, The Principles of Nuclear Magnet-ism,Oxford University Press, Oxford, 1961

[4] T. Pietraß, A. Bifone, A. Pines, Surf. Sci. Lett. 334, L730 (1995)

[5] C. P. Slichter, Ann. Rev. Phys. Chem. 37, 25 (1986)

[6] U. Ruth, T. Hof, J. Schmidt, D. Fick and H. J. Jänsch, Appl. Phys. B 68, 93 (1999)

[7] P. B. Gerhard, Konventionelle Puls-NMR an 129Xe auf Einkristalloberflächen, PhD thesis, Philipps-Universität, Marburg, 2003

[8] B. M. Goodson, J. Magn. Reson. 155, 157 (2002)

[9] H. J. Jänsch, T. Hof, U. Ruth, J. Schmidt, D. Stahl, D. Fick, Chem. Phys. Lett. 296, 146 (1998)

[10] D. Stahl, W. Mannstadt, P. Gerhard, M. Koch, H. J. Jänsch, J. Magn. Reson. 159, 1 (2002)

[11] H. J. Jänsch, P. Gerhard, M. Koch, D. Stahl, Chem. Phys. Lett. 372, 325 (2003)

[12] A. Bifone, T. Pietrass, J. Kritzenberger, A. Pines, B. F. Chmelka, Phys. Rev. Lett. 74, 3277 (1995)

[13] Y. Y. Tong, C. Rice, A. Wieckowski, E. Oldfield, J. Am. Chem. Soc. 122, 1123 (2000)

[14] H. J. Jänsch, P. Gerhard, M. Koch, submitted (2004)

[15] H. Arnolds, H. J. Jänsch, Chem. Phys. Lett. 272, 13 (1997)

[16] H. Arnolds, D. Fick, H. Unterhalt, A. Voß, H. J. Jänsch, Solid State Nucl. Mag. Res. 11, 87 (1998)

[17] H. D. Ebinger, H. Arnolds, C. Polenz, B. Polivka, W. Preyß, R. Veith, D. Fick, H. J. Jän-sch, Surf. Sci. 412/413, 586 (1998)

[18] G. Kirchner, M. Czanta, G. Dellemann, H. J. Jänsch, W. Mannstadt, J. J. Paggel, R. Platzer, C. Weindel, H. Winnefeld, D. Fick, Surf. Sci. 494, 281(2001)

[19] H. J. Jänsch, G. Kirchner, O. Kühlert, M. Lisowski, J. J. Paggel, R. Platzer, R. Schillinger, H. Tilsner, C. Weindel, H. Winnefeld, D. Fick, Nucl. Instrum. Meth. B 171, 537 (2000)

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Papers for Publication

• “Preparation of submicron-structured alkylsi-loxane monlayers using prepatterned silicon sub-strates by laser direct writing,” T. Balgar, S.Franzka, N. Hartmann, E. Hasselbrink, Lang-muir, accepted

• “Laser-etched silicon pillars and their porosifica-tion,” D. Mills, K. W. Kolasinski, J. Vac. Sci. Tech-nol. A, accepted

• “Laser-assisted restructuring of silicon overnano-, meso- and macro-scales,” K. W.Kolasinski, Recent Research Developments inApplied Physics, accepted

• “Laser-etched silicon pillars and their porosifica-tion,” D. Mills, K. W. Kolasinski, J. Vac. Sci. Tech-nol. A, accepted

• “A simple and compact mechanical velocityselector of use to analyze/select molecular align-ment in supersonic seeded beams,” F. Pirani, D.Cappelletti, F. Vecchiocattivi, L. L. Vattuone, A.Gerbi, M. Rocca, U. Valbusa, Rev. Sci. Instr.,accepted

• “Stereo dynamical effects in the adsorption ofethylene molecules on metal surfaces,” L.Vattuone, A. Gerbi, M. Rocca, U. Valbusa, D.Cappelletti, F. Vecchiocattivi, F. Pirani, submitted

• “Enhanced reactivity at metal-oxide interface:Water interaction with MgO ultrathin films,” L.Savio, E. Celasco, L. Vattuone, M. Rocca, sub-mitted

• “Direct access into subsurface sites in gas-sur-face interaction: O2/Ag(210),” L. Vattuone, L.Savio, M. Rocca, Phys. Rev. Lett., accepted

• “Steering effects in the C2H4 interaction withAg(410),” L. Savio, L. Vattuone, M. Rocca, C.Corriol, G. Darling, S. Holloway, Chem. Phys.Lett., accepted

• “Enhanced hydrolysis at MgO films,” L. Savio, E.Celasco, L. Vattuone, M. Rocca, J. Chem. Phys.,accepted

• “Oxygen vibrations in O-Ag(001),” D. Loffreda, A.Dal Corso, S. Baroni, L. Savio, L. Vattuone, M.Rocca, Surf. Sci., accepted

• “Dynamics of the interaction of O2 with flat andstepped Ag surfaces,” L. Vattuone, L. Savio, M.

Rocca, The Chemical Physics of Solid Surfaces,ed. Ph. Woodruff, Vol. 11, Chap. 8, 223-246

• “Depolarisation of the spatial alignment of therotational angular momentum vector by hyperfineinteraction,” M. Rutkowski, H. Zacharias, Chem.Phys., in press

• “Tuneable, narrow-band, picosecond pulses inthe mid-IR by difference frequency mixing inGaSe and CdSe,” K. Finsterbusch, A. Bayer, H.Zacharias, Appl. Phys. B, submitted

• “Molecular dynamics simulations of palladiumcluster growth on flat and rough graphite sur-faces,” P. Brault, G. Moebs, Eur. Phys. J. Appl.Phys., submitted

• “Why Au and Cu are more selective than Pt forpreferential oxidation of CO at low temperature,”S. Kandoi, A. A. Gokhale, L. C. Grabow, J. A.Dumesic, M. Mavrikatis, Cat. Lett., in press

• “Competitive paths for methanol decompositionon Pt(111),” J. Greeley, M. Mavrikakis, J. Am.Chem. Soc., in press

• “The adsorption and dissociation of O2 on Pt-Coand Pt-Fe alloys,” Y. Xu, A. V. Ruban, M. Mavri-kakis, J. Amer. Chem. Soc., in press

• “From atomic scale reactant ordering to mesos-cale reaction front propagation: CO-oxidation onPd(100),” D.-J. Liu, J. W. Evans, Phys. Rev. Lett.,submitted

• “Lattice-gas modeling of CO-adlayers onPd(100),” D.-J. Liu, J. Chem. Phys., submitted

• “Lattice-gas modeling of the formation and order-ing of oxygen adlayers on Pd(100),” D.-J. Liu, J.W. Evans, Surf. Sci., submitted

• “Kinetics of the CO oxidation reaction on Pt(111)studied by in-situ high resolution x-ray photoelec-tron spectroscopy,” M. Kinne, T. Fuhrmann, J. F.Zhu, C. M. Whelan, R. Denecke, H.-P. Steinrück,J. Chem. Phys., accepted

• “D2O adsorption and coadsorption with CO stud-ied by in-situ high resolution x-ray photoelectronspectroscopy,” M. Kinne, T. Fuhrmann, B. Trünk-enschuh, J. F. Zhu, R. Denecke, H.-P. Steinrück,Langmuir, in print

• “Vibrationally resolved in-situ XPS study of acti-vated adsorption of methane on Pt(111),” T.

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Gas-Surface News

Fuhrmann, M. Kinne, C. M. Whelan, J. F. Zhu, R.Denecke, H.-P. Steinrück, Chem. Phys. Lett.,submitted

• “A theoretical study of CO oxidation on Au nano-particles supported by MgO(100),” L. M. Molina,B. Hammer, Phys. Rev. B, accepted

• “Adsorption of O2 at Au nanoparticles supportedon TiO2(110) and oxidation of CO: A DFT study,”L. M: Molina, M. D. Rasmussen, B. Hammer, J.Chem. Phys., accepted

• “Two-step reaction on a strained, nano-scalesegmented surface,” C. Africh, F. Esch, W. X. Li,M. Corso, B. Hammer, J. Chem. Phys., accepted

• “Insight into H2O-ice adsorption on metal sur-faces from first principles simulations,” A.Michaelides, A. Alavi, D. A. King, in press

• “A first principles study of H2O diffusion on ametal surface: H2O on Al{100},” A Michaelides, V.A. Ranea, P. L. de Andres, D. A. King, in press

• “Water dimer diffusion on Pd{111} assisted by H-bond donor-acceptor tunneling exchange,” V. A.Ranea, A. Michaelides, P. L. de Andres, R. Ram-irez, J. A. Verges, D. A. King, submitted

• “Acetaldehyde chemistry on Ag{111}-(4x4)-Ag1.830 between 77 and 200K studied by STM,”M. J. Webb, S. M. Driver, D. A. King, in press

• “Theory of methane dehydrogenation onPt{110}(1x2) - Part I: Chemisorption of CHx(x=0-3),” M. A. Petersen, S. J. Jenkins, D. A. King,submitted

• “The theory of methane dehydrogenation onPt{110}(1x2) - Part II: Microscopic reaction path-ways for CHx decomposition (x=1-3),” M. A.Petersen, S. J. Jenkins, D. A. King, submitted

• “A DFT study of the interaction of monomericwater with the Ag(111) surface,” V. A. Ranea, A.Michaelides, R. Ramirez, D. A. Verges, P. L. deAndres, D. A. King, submitted

• “Broadband femtosecond sum frequency spec-troscopy of CO on Ru{1010} in the frequencyand time domains,” J. P. R. Symonds, H. Arnolds,V. L. Zhang, K. Fukutani, D. A. King, accepted

• “Femtosecond pump-probe spectroscopy of COon Ru{1010}, from experimental and theoretical

perspectives,” Festschrift for Gerhard Ertl, J. P.R. Symonds, H. Arnolds, D. A. King, submitted

• “Hot-atom vs Eley-Rideal dynamics in hydrogenrecombination on Ni(100): 1. The single-adsorb-ate case,” R. Martinazzo, S. Assoni, G. Rarinoni,G. F. Tantardini, J. Chem. Phys., submitted

• “Effect of surface defects in heterogeneouscatalysis,” U. Burghaus, Nova Science Publish-ers Inc., in press

• “The interaction of water with the oxygen-termi-nated, polar surface of ZnO,” M. Kunat, St. GilGirol, U. Burghaus, Ch. Wöll, J. Phys. Chem., inpress

• “Negative band-gaps in dilute InNxSb1-x alloys,”T. D. Veal, I. Mahboob, C. F. McConville, Phys.Rev. Lett., accepted

• “Fuchs-Kliewer phonon excitations in GaNAsalloys,” I. Mahboob, T. D. Veal, L. F. J. Piper, C. F.McConville, M. Hopkinson, Appl. Phys. Lett.,accepted

• “Electronic spectroscopy of dilute nitrides,” T. D.Veal, I. Mahboob, L. F. Piper, T. Ashley, M. Hop-kinson, C. F. McConville, J. Phys: Cond. Matt. -Inv. Rev., accepted

• “Indium nitride: Evidence for electron accumula-tion,” T. D. Veal, L. F. J. Piper, I. Mahboob, C. F.McConville, H. Lu, W. J. Schaff, J. Vac. Sci. Tech-nol. B, accepted

• “CO and hydrogen adsorption on Pd(210),” M.Lischka, C. Mosch, A. Groß, Surf. Sci., submitted

• “Quantum theory of scattering and adsorption atsurfaces,” A. Groß, submitted

• “Methanol reactions over oxygen-modified Resurfaces: Influence of surface structure and oxi-dation,” A. S. Y. Chen, W. Chen, H. Wang, J. E.Rowe, T. E. Madey, J. Phys. Chem. B, submitted

• “Abstraction of oxygen from dioxygen on Al(111)revealed by REMPI laser spectrometry,” M.Binetti, E. Hasselbrink,submitted

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Gas-Surface News

11

The Third San Luis Symposium on Surfaces, Interfaces and Catalysis will be held in Mérida, Venezuela,between March 15 and March 19, 2004. This is the third of a continuing series of symposia designed tostrengthen the ties among surface scientists in the US, Europe and Latin America. The research areas coveredwill include:Theoretical methods in surface scienceNovel experimental techniques, including model systemsHeterogeneous catalysisSurface science in semiconductors, tribology, biology, and other fields

Please note that the deadline for abstract submission is January 31, 2004.

Visit our web site at: http://www.zaera.chem.ucr.edu/SanLuisIII/index.shtml

Professor Francisco ZaeraDepartment of ChemistryUniversity of California

Riverside, CA 92521phone: (909) 787-5498

fax: (909) 787-3962 (direct)(909) 787-4713 (department)

e-mail: francisco.zaera@ucr.eduweb site: http://zaera.chem.ucr.edu/

Gas-Surface News

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Surface Structures

Wednesday 24th March 2004

School of Chemistry, University of Nottingham

Royal Society of Chemistry

Solid Surfaces Group (SSG)

Institute of Physics

Thin Films and Surfaces Group(TFSG)&Invited Speakers:

Dr. Georg Held, Cambridge

Prof. Rasmita Raval, Liverpool

Prof. Geoff Thornton, Univ. Coll. London

The theme is surface structures, from adatoms in UHV to biomolecular surfaces at ambient pressure. The organising committee

comprises, Martin McCoustra, Rob Jones and Peter Milligan.

Contributed papers are invited; either oral (15 min + 5 min questions) or posters. Please send a one page abstract (with

presenter, other authors, title, institution and whether it’s a presentation, a poster, or either), as a word attachment, to

Robert.G.Jones@nottingham.ac.uk by Friday March 5th. The organising committee will devise the programme from these

contributions.

The meeting will start at 10.30 am and finsh at 5.30 pm.

Registration fees, which includes lunch, coffee and tea breaks, will be as

follows:

Member of SSG or TFSG……………………..……. £25

Member of RSC or IOP( but not of SSG or TFSG)…£30

Non Members of RSC or IOP……………………….£40

Please fill in, and return, the attached application form.

Gas-Surface News

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EGU General Assembly:

Microphysics and Heterogeneous Chemistry of Aerosols

Nice, 25-30 April 2004We would like to invite you to participate in the session AS3.01, Microphysics and heterogeneous chemistry ofaerosols, at the EGU General Assembly in Nice, 25-30 April 2004.A large number of atmospheric physical and chemical processes involve aerosols. It is therefore the aim of thissession to provide an annual forum where recent and exciting advances in our knowledge of tropospheric aer-osols can be discussed. We invite contributions covering the following areas:

Microphysics: The physical state of aerosols is of central importance for describing their potential impact ontropospheric chemistry and cloud particle formation. We encourage the presentation of new advances dealingwith nucleation processes, phase transformations, optical properties, particle structure, chemical composition,and aerosol/cloud particle interactions.

Chemistry and modelling: The composition of aerosols is very variable over a wide range leading to a largenumber of possible chemical reactions. We therefore encourage presentations focussed on multi-phase or heter-ogeneous processes in/on mineral, dust, organics, soot, sulfate, sea-salt and cloud particles. Due to the com-plexity of the troposphere, we also invite modelling contributions as tools for highlighting potential effects (ortheir absence) of aerosols on tropospheric chemistry. Laboratory studies, field measurements, and modellingstudies will all receive equal priority. This session will cover the whole range of conditions from the earth sur-face up to the lower stratosphere. The different topics will bring together scientists from various disciplines inan effort to focus on these important problems in atmospheric chemistry.

Invited speakers include:

Markku Kulmala from the University of Helsinki, contributing on: How do particles nucleate and grow?Charles Zender from the University of California at Irvine, contributing on: The impact of dust on atmosphericchemistry.The deadline for abstracts is on JANUARY 11th, 2004.Details about the conference and submission of abstracts can be found at:http://www.copernicus.org/EGU/ga/egu04/programme/overview.htmlThomas Koop (koop@atmos.umnw.ethz.ch) and Christian George (Christian.George@univ-lyon1.fr)

A new journal, a new concept: http://www.atmos-chem-phys.org/

Christian GEORGELaboratoire d'Application de la Chimie de l'Environnement (LACE)

Domaine Scientifique de la Doua - Bâtiment J. Raulin43 Bd du 11 Novembre 1918F-69622 Villeurbanne Cedex

Francetel: (33) (0)4 72 43 1489

fax: (33) (0)4 72 44 81 14mailto: Christian.George@univ-lyon1.fr

Gas-Surface News

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July 4-9 2004, Genova, Italy, UEJointly organized by the Department of Physics of the University of Genova

andIstituto Nazionale per la Fisica della Materia

with the collaboration ofCNR - Istituto per la Microelettronica e Microsistemi

andINFN - Istituto Nazionale di Fisica Nucleare - Sez. di Genova

ICACS is a biannual meeting, which deals with physical and chemical phenomena induced by the interaction of low andhigh enery beams of charged or neural particles with the surface and the bulk of solids, liquids and biomaterials. The mostrecent meetings have been held in Puri (India, 2003), Paris (France, 2001), Odense (Denmark, 1999) and Beijing (China,1997). The objectives of the ICACS-21 edition are to assess the state of the art in the current understanding of a variety ofphenomena such as energy losses of ions, radiation damage, sputtering, excitation, ionisation and electron emission as wellas collision induced reactions and desorption of charged or neutral atomic and molecular species. Fundamental aspects ofelectron transfer in particle surface/bulk interactions will be highlighted. New developments in experimental techniquesmay be presented. While the programme will focus mainly on the interaction of atomic, molecular and cluster projectiles,related processes induced by electron, positron and photon beams, will also be considered. Pertinent materials are pristineor adsorbate covered metals, semiconductors, insulators, as well as polymers, bio-materials and liquids. Macro to nanostructures of these materials will be considered. While the emphasis of the meeting is on fundmental processes, challengingscientific and technological applications in physics, chemistry, biology and medicine will be considered. The programmewill consist of oral and poster presentations and sufficient time for informal discussions will be allocated.

Tutorial Lectures:A series of tutorial lectures will be given on Sunday, the 4th July. These will be open to all registered participants, althoughthey will be mainly aimed at students and postdocs. Their objective is to present clear overviews of certain areas of ICACSon a non-specialised level.For further information please refer to: http://www.ge.it/icacs21/

Gas-Surface News

The 8th World Multi-Conference on SYSTEMICS , CYBERNETICS And INFORMATICS

SCI 2004

http://www.iiis.org/sci2004/

July 18 - 21, 2004, Orlando, Florida(USA)

The Rosen Plaza Hotel, http://www.rosenplaza.com/frames1.htmlProgram Committee Chair: William LessoGeneral Chair: Nagib CallaosOrganizing Committee Chair: Belkis SanchezPROGRAM COMMITTEE: Integrated by (320) prestigious scholars/researchers from 54 countries

MAJOR THEMES

* Information Systems, Technologies and Applications* Communication and Network Systems, Technologies and Applications* Control Systems, Technologies and Applications* Computer Science and Engineering* Optical Systems, Technologies and Applications* Image, Acoustic, Speech and Signal Processing* Applications of Informatics and Cybernetics in Science and Engineering* Systemics

PARTICIPANTS

Participation of both, researchers and practitioners is strongly encouraged. Papers may be submitted on:research in science and engineering, case studies drawn on professional practice and consulting, and positionpapers based on large and rich experience gained through executive/managerial practices and decision-mak-ing. For this reason, the Program Committee is conformed according to the criteria given above.

EXTENDED ABSTRACTS AND PAPER DRAFTS SUBMISSION FORM

Extended abstracts or paper drafts should be sent taking into account the following format:1. Major theme of the paper should be related to at least one of the major themes given above.2. Paper title.3. Extended abstract of 500 to 1500 words and/or paper drafts of 2000 to 5000 words, in English.4. Author(s) and/or co-author(s) with names, addresses, telephone and fax numbers, and e-mail addresses.Extended abstracts or paper drafts should be sent via the conference web site http://www.iiisci.org/sci2004/,filling the respective form and uploading the respective paper or extended abstract. If the conference web siteis not accessible for you, you can also make your submission by e-mail, attaching it to the following e-mailaddresses: sci2004@telcel.net.ve, sci2004@cantv.net and sci2004@iiis.org.

DEADLINES

December 10th, 2003: Submission of extended abstracts (500-1500 words) or paper drafts (2000-5000 words).December 10th, 2003: Invited Sessions proposals. Acceptation of invited session proposals will be done in aboutone week of its registration via the respective conference web form and final approval will be done after theregistration of at least five papers in the respective session.January 30th, 2004: Acceptance notifications.March 31st, 2004: Submission of camera-ready papers: hard copies and electronic versions.

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Gas-Surface News

PAPERS REVIEWING AND PUBLICATION

Submitted papers will be sent to reviewers. Accepted papers, which should not exceed six single-spaced typedpages, will be published by means of paper and electronic proceedings.SCI Journal will publish, at least, the best 10% of the papers presented at the conference.

INVITED SESSIONS

Based on past conferences experience, we suggest the following steps in order to organize an invited session:1) Identify a special topic in the scope of SCI 2004 and the invited session title.2) Fill the invited session organization form, provided in the conference web page http://www.iiisci.org/sci2004/ and fill the respective form. If by any reasons you are not able to access the page mentioned above,please try the following page: http://www.iiis.org/sci2004/. If you don't have access to the web, contact us viae-mail.Invited sessions and symposia organizers with the best performance will beco-editors of the proceedings vol-ume where their session or symposia paper were included.Best invited sessions and symposia organizers are candidates for invited editors or co-editors of the SCI Jour-nal special issue related to their field of research interest.

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Gas-Surface News

17

Donostia International Physics Center Workshop

MOLECULE-SURFACE INTERACTIONS: ELEMENTARY REACTIVE PROCESSES

Donostia/San Sebastián, September 7-11, 2004

http://dipc.sw.ehu.es/dipc/molecule-surface-interactions.htm

Co-chairmen: Pedro Miguel ECHENIQUE (Donostia/San Sebastián, Spain)Antoine SALIN (Bordeaux, France)

Conference Secretary: Heriberto Fabio BUSNENGO (Rosario, Argentina)

Scientific committee: Daniel FARÍAS (Madrid, Spain) Axel GROSS (München, Germany)Geert Jan KROES (Leiden, The Netherlands) Mario ROCCA (Genova, Italy)

Reactivity at gas-solid interfaces plays a fundamental role in a large number of natural processes: heterogenouscatalysis, atmospheric reactions, interstellar matter, biological or geological media. Recently, reactivity studies have greatlybenefited from the development of individual atom, molecule or radical manipulation and reaction control on surfaces. Thelatter technique allows to pilot step by step chemical reactions, to observe elementary reactions in real time, to constructnanostructured catalysts, etc. Molecular beams allow to simulate elementary steps in catalytic processes like the formation andstabilization of reactive radicals or direct reactions between adsorbates and atoms/molecules of the gas phase. On the otherhand, theoretical methods for the determination of the electronic structure of adsorbates on surfaces have reached the pointwhere they are able to deal with complex situations, like the determination of reactive paths, even when the latter involvedefects or local modifications of the surface. The concerted theoretical and experimental approach has proved to be verysuccessful for the elucidation of elementary microscopic reaction steps of molecules at surfaces. In this workshop, the currentstate of the art in both theory and experiment will be reviewed and promising new developments discussed.

Topics: * Dynamics of molecular adsorption and desorption processes* Elementary reactions involved in fundamental and catalytic processes* Molecular vibration on surfaces* Dissipation processes* Electronic excitations and relaxations, photochemistry* Scattering of molecules from surfaces. Phonon excitations* Surface diffusion

The Workshop, planned for about 60 participants with ample time for discussions, will consist in 3 key-note lectures,about 18 additional invited talks and poster sessions. Invited Speakers that have confirmed their participation are:A. Kleyn………………………Reactive processes at the surfaces of a fusion reactor (key-note lecture)J. K. Norskov………………...From elementary reaction steps to a full catalytic reaction (key-note lecture)K.H. Rieder…………………..STM control of chemical reactions (key-note lecture)R. Beck ……………………….State Resolved Studies of Molecule-Surface Reaction Dynamics (invited talk)N. Lorente and J.I. Pascual….Inducing controlled atomic dynamics by an electron current (invited talk)H. Nienhaus…………………..Electronic excitations by reactive particle-surface interactions (invited talk)R. A. Olsen……………………Why rough surfaces make good catalysts? (invited talk)M. Persson…………………….title to be confirmed (invited talk)K. Reuter…………………..….The steady-state of heterogeneous catalysis, studied by first-principles

statistical mechanics (invited talk)L. Savio…………………….…Adsorption dynamics of simple molecules at surfaces with well defined

defects: O2 and C2H4/Ag(n10) (invited talk)G.O. Sitz………………………State resolved studies of the scattering of D2 and HD from Pd(111) (invited talk)

Additional information can be obtained from the Workshop Web site: http://dipc.sw.ehu.es/dipc/molecule-surface-interactions.htm or by E-mail: dipc2004@ifir.edu.ar.

Gas-Surface News

PhD Student Surface Science at the University of Groningen

Research project: Understanding the influence of the molecular character on the solid state properties oforganic crystalline films The aim of this project is to contribute the understanding of the underlying physics ofcharge injection as well as the nature of the electronic states and magnetic properties in pure and dopedorganic crystalline films. The successful candidate will deposit thin organic films with the help of a supersonicmolecular beam and characterize them by various types of electron spectroscopies will be used, both in thehome laboratory and at several modern synchrotron radiation facilities in Europe. IR measurements, STMinvestigations and X-ray diffraction studies will also be carried out.This project is part of an international research project (partners in Spain, Italy and Slovenia). Required education/skills: University Graduate. Candidates must have a masters degree in physics. Experi-ence with ultra high vacuum techniques and/or electron spectroscopies is desirable. Further relevant qualifica-tions are communicative and cooperative skills and the ability to prioritize.The position is for 4 years, subject to the assessment, after one year, of the progress of the PhD student and ofthe project. The successful candidate will participate in the training program of the Groningen Materials Sci-ence Centre (MSC) see http://www.rug.nl/msc/education/PhDCourses/.Deadline for application: March 5th, 2004 (motivation letter, CV with publication list, names and addresses oftwo referees).Additional information can be obtained through one of the following links. About the organization (http://www.rug.nl)About the Materials Science Centre (http://www.rug.nl/msc/) For detailed information please contact :

Prof. Dr. Petra RudolfMaterials Science CentreUniversity of Groningen

Nijenborgh 49747 AG Groningen

The Netherlandsphone: : +(31) 50 363 4974

fax: +(31) 50 363 4879e-mail: P.Rudolf@phys.rug.nl

Working at the University of Groningen (RUG) means working at the frontiers of knowledge. The RUG offersresearchers and students the opportunity to expand those frontiers, to develop their talents and together withothers realise top quality achievements. The RUG therefore deliberately opts for an interdisciplinary approachto knowledge. Discoveries are born and innovation realised at the interfaces between the various scientificfields. Researchers and students in Groningen benefit from the rich assortment of disciplines that the RUG hasbuilt up since its founding nearly four hundred years ago. Knowledge is universal and transcends boundaries.The RUG has deliberately chosen to make a priority of intensive and worldwide co-operation with other lead-ing universities and organisations. As well as being outward looking, the RUG is also closely involved with itsown region where it is one of the largest employers. The university’s 20000 students and 5000 staff have a dis-tinct academic identity, firmly rooted in the wider social context. They are a vital element of the vibrant city ofGroningen – a great place for students and staff.

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Gas-Surface News

19

PhD and post doctoral positions

A PhD studentship and a post doctoral position will be available for 3 years (beginning in March 04) at theLaboratoire de Recherches sur la Reactivite des Solides in Dijon (France) in the Surface and Interface Group.This work is set within the framework of the European FP6 program “Nanostructures for Chemical Sensors”(NanoChemSens).

This program is pertaining to the identification and development of the appropriate surface science tools andnanotechnological processes of future nanodevices for chemical sensing by understanding those nano-scalephenomena that control nanostructured sensors and functionalized surfaces.

The research activities in Dijon will focus on surface studies of nanostuctured sensors based on MoOx

nanowires and nanodots on TiO2 single crystal surfaces and on the interaction of small molecules with thesesystems. A variety of experimental methods will be applied including deposition using either physical orchemical methods as well as characterizations using low energy electron diffraction (LEED), Auger electronspectroscopy (AES) and X-ray or UV photoelectron spectroscopy partly using synchrotron radiation.

In addition to research in Dijon, periods of work in the partner laboratories will take place.

For more enquiries and applications contact:

Sylvie BOURGEOIS or Bruno DOMENICHINISylvie.Bourgeois@u-bourgogne.fr

Bruno.Domenichini@u-bourgogne.frLaboratoire de Recherches sur la Réactivité des Solides

UFR Sciences et TechniquesBP 47870, 21078 DIJON Cedex

FRANCEhttp://www.u-bourgogne.fr/REACTIVITE/siom

Gas-Surface News

Friedrich-Alexander-UniversitätErlangen-Nürnberg

INSTITUT FÜR PHYSIKALISCHEUND THEORETISCHE CHEMIE

Postdoctoral-Position

A postdoctoral position (Wiss. Assistent, C1) is available at the Institute of Physical Chemistry in the group of Prof. Hans-Peter Steinrück. The research activities focus on surface and interface science. Besides studies of single crystal and polycrystalline surfaces, we are particularly interested in designing new materials with novel electronic, geometric and chemical properties. Special attention is paid on tailoring of these properties on the nanometer scale. The materials include ultrathin metal and oxide layers on metal substrates as well as molecular layers on metals. We apply a variety of experimental methods, including high resolution X-ray photoelectron spectroscopy (XPS) and angle-resolved UV photoelectron spectroscopy (ARUPS), partly using synchrotron radiation, as well as low energy electron diffraction (LEED), molecular beam techniques and scanning tunneling microscopy (STM). The candidate is expected to participate in running research programs and to establish new activities within the research group.Candidates with a PhD in physics or physical chemistry, who are interested in joining an interdisciplinary research team should contact:

Prof. Dr. Hans-Peter Steinrück Institut für Physikalische und Theoretische Chemie

Universität Erlangen-Nürnberg Egerlandstraße 3 D-91058 Erlangen

GermanyTel.: ++49-9131-85-27343

Email: steinrueck@chemie.uni erlangen.dehttp://www.chemie.uni-erlangen.de/pc2

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Gas-Surface News

PHILIPPS-UNIVERSITÄT MARBURG

FACHBEREICH PHYSIK

Stellenausschreibung

Im Fachbereich Physik der Philipps-Universität Marburg ist zum nächstmöglichen Zeitpunkt -befristet auf 3 Jahre -(Verlängerung um weitere 3 Jahre möglich) die Stelle eines/einer

Wissenschaftlichen Assistenten/-in (C1 BBesGes)(Angestellten oder Beamtenverhältnis auf Zeit gem. § 41 HUG)

zu besetzen.

Unter der Leitung von Prof. Dr. P. Jakob wird eine neue Arbeitsgruppe auf dem Gebiet der experimentellen Oberflächenphysik aufgebaut. Forschungsschwerpunkte sind die Erzeugung funktionalisierter Festkörperoberflächen und epitaktisch gewachsener dünner Filme und deren Charakterisierung mittels verschiedener optischer Methoden und STM. Die bisherigen, eher katalytisch motivierten Arbeiten zu bimetallischen Schichtsystemen sollen nun auf organische Filme und deren elektronische, strukturelle und optische Eigenschaften ausgedehnt werden.

Die Arbeitsgruppe ist Teil des Wissenschaftlichen Zentrums für Materialwissenschaften und des Interdisziplinären Forschungszentrums Optodynamik der Philipps-Universität.

Aufgabengebiet:

Wissenschaftliche Dienstleistungen in Forschung und Lehre, die auch dem Erwerb einer weiteren wissenschaftlichen Qualifikation auf dem Gebiet der Experimentalphysik dienen (Habilitation); Durchführung von Experimenten an Festkörperoberflächen und dünnen Filmen; Beteiligung am Aufbau einer Epitaxie-Anlage für das Wachstum polyzyklischer Kohlenwasserstoffe unter XHV-Bedingungen.

Voraussetzungen:

Qualifizierte Promotion auf dem Gebiet der Experimentalphysik oder physikalischen Chemie. Erfahrungen in der Ultrahochvakuumtechnik. Bereitschaft zur Mitarbeit an interdisziplinären Forschungsprojekten.

Bewerbungen mit den üblichen Unterlagen bitte bis zum 20.02.2004 mit dem Kennzeichen Ja1/04 an den Dekan des Fachbereichs Physik der Philipps-Universität, Renthof 5, 35032 Marburg/Lahn, senden. Weitere Informationen werden gerne unter 06421/28-24328 oder peter.jakob@physik.uni-marburg.de erteilt.

Der Frauenförderplan der Philipps-Universität verpflichtet zur Erhöhung des Frauenanteils. Frauen sind deshalb ausdrücklich zur Bewerbung aufgefordert.

Schwerbehinderte Bewerber(innen) werden bei gleicher Eignung bevorzugt.

_________________________________________________________________________________________________________

Tel.: +49-6421-2824328, Fax: +49-6421-2824218, email: peter.jakob@physik.uni-marburg.de

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Gas-Surface News

Eindhoven University of TechnologySimulating Zeolite Synthesis

Experimental evidence suggests that there may be three stages in zeolite synthesis. First small silicate clustersare formed that contain several dozen silicon atoms. These clusters then aggregate to form new clusters with alinear dimension that is typically four times as large. Finally these larger clusters combine to form the zeolitecrystal. The reason why there are these stages is not known.

We are looking for a Ph.D. student to simulate this zeolite synthesis, and to study how temperature, pH, andthe template molecule affect the process. The work will involve the development of potential-energy surfacesto describe the formation of the silicate framework, and the implementation of an off-lattice kinetic MonteCarlo approach for the simulations. If you are interested in this project, and you are an enthusiastic and hard-working person with a solid background in theory and computations (preferably with programming experi-ence), please send your CV and a short description of your research interests to:

Dr. A. P. J. JansenEindhoven University of Technology

Laboratory of Inorganic Chemistry and Catalysis Theory Group P.O. Box 513

5600 MB EindhovenThe Netherlands

http://www.tue.nl/http://www.catalysis.nl/~theory/

tel.: +31 40 2475037fax: +31 40 2455054

email: a.p.j.jansen@tue.nl

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Leiden University

Cholesterol: the regulator of biomembrane structure?

It is a three-year post-doctoral position (PhD applicants are also welcome), to study the role of cholesterol inthe formation and functioning of biological membranes by surface-specific vibrational spectroscopies usingfemtosecond lasers. Preliminary results have recently been published (Vibrational spectroscopic investigationof the phase diagram of a biomimetic lipid monolayer. Phys. Rev. Lett. 90, 128101 (2003).) The work is done inclose collaboration with Swammerdam Institute for Life Sciences in Amsterdam. Applicants ideally have abackground in either surface or non-linear spectroscopic techniques, preferably Sum-Frequency Generation, orin the field of membrane biophysics/chemistry.

A brief description of the project:The aim of the project is to elucidate the role of cholesterol in regulating the structure and function of lipidbilayers constituting a cell membrane. A typical membrane contains - in addition to phospholipids - up to 40%cholesterol.

Cholesterol affects the structural parameters of membranes, which are of fundamental importance to biologicalfunctions, e.g. in sorting, signalling and the incorporation of viral structural proteins. Cholesterol - eitherthrough complex formation with specific lipids or by influencing the line tension of liquid-liquid phase sepa-rated lipid microdomains - plays a key role in modulating, and possibly regulating, membrane local structure.Despite its apparent importance, the precise mechanism of the effects of cholesterol in membranes haveremained largely unexplored. We will use a combination of highly innovative techniques - coherent anti-StokesRaman scattering (CARS) and sum-frequency generation (SFG) - and a variety of fluorescence techniques todirectly address the role of cholesterol in membrane functioning.

Dr. Mischa BonnLeiden Institute of Chemistry

P.O. Box 95022300 RA LeidenThe Netherlands

tel. +31 71 527-4224fax +31 71 527-4451

e-mail: m.bonn@chem.leidenuniv.nl

Gas-Surface News

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Postdoctoral Research Positions (2)

Science Foundation Ireland Nanoscience Centre

University Of Dublin, Trinity College, Dublin, Ireland

Contact, transport and energy dissipation in molecular systems. This project involves UHV STM and CAFMmeasurements of transport in molecules, together with DFT modelling. Applicants should have background inUHV STM or related experience.

Mechanical/chemical modification and electrical characterisation of nanoscale wires and networks. Thisproject involves wire fabrication, functionalisation and electromechanical characterisation using a nano-manipulation AFM. Applicants should have expertise in electrical measurements.

The successful candidate will build on a strong experimental program emphasizing the application of scanningprobe methods to nanoscale materials processing and characterization. We seek motivated individuals withwell-developed analytical and technical skills who seek an opportunity to make a substantial scientific contri-bution. A Ph. D. in physics, chemistry or a closely related area of materials science or electrical engineering, isrequired. All inquiries should include a curriculum vitae, publication list and complete contact information forthree references.

The TCD Nanoscience Centre has full lithographic capabilities (including e-beam and focussed ion beamprocessing), scanning probe systems (including cryogenic and variable temperature STMs, an entire suite ofAFM capabilities, including closed-loop manipulation), and chemical synthesis facilities.

For further details contact:Prof. John J. Boland

Chemistry DepartmentTrinity College Dublin

IrelandE-mail: jboland@tcd.ie

Gas-Surface News

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UNIVERSITY COLLEGE LONDON

LONDON CENTRE FOR NANOTECHNOLOGY

PhD POSITION IN STM and STM-IETS

A three year studentship is available as part of the EU ramework 6 NANOSENS Network.Work in London will focus on studies of the interaction of small molecules with metal/oxideinterfaces. The principal techniques to be used are STM and single molecule vibrationalspectroscopy (STM-IETS). In addition to work in London, the studentship will involve peri-ods of work at the partner laboratories in Padova, Düsseldorf, Dijon, Marseille, Prague andCopenhagen.The position will be available after 1 December 2003. The studentship covers fees for an EUstudent and approx 18,000 euros per year after tax .Please contact Professor Geoff Thornton (g.thornton@ucl.ac.uk).

Diary Page

15th-19th March 2004

The Third San Luis Symposium on Surfaces, Interfaces and Catalysis, Mérida, Vene-zuela

Please contact: Professor Francisco Zaera, Department of Chemistry, University of Califor-nia, Riverside, DA 92521, USA, phone: +1 909 787-5498, fax: +1 909 787-3962/ -4713, e-mail: francisco-zaera@ucr.edu, web site: http://www.zaera.chem.ucr.edu/SanLuisIII/index.shtml24th March 2004

Surface Structures, School of Chemistry, University of Nottingham

25th-30th April 2004

EGU General Assembly: Microphysics and Heterogeneous Chemistry of Aerosols, Nice

For further information please refer to the web site: http://www.copernicus.org/EG/ga/egu04/programme/overview.html or get in touch with Thomas Koop(koop@atmos.umnw.ethz.ch) or Christian George (Christian.George@univ-lyon1.fr)28th June - 2nd July 2004

16th International Vacuum Congress (IVC-16)/12th International Conference on SolidSurfaces (ICSS-12)/8th International Conference on Nanometer-Scale Science and Tech-nology (NANO-8)/17th National Vacuum Symposium (AIV-17), Venice, Italy

web site: http://www.ivc16.org4th-9th July 2004

icacs21 - International Conference on Atomic Collisions in Solids, Genova, Italy

For further information please refer to http://www.ge.infm.it/icacs21/18th-21st July 2004

The 8th World Multi-Conference on Systemics, Cybernetics and Informatics SCI 2004,Orlando, Florida (USA)

For registration please refer to the followint page: http://www.iis.org/sci2004/7th-11th September 2004

Donostia International Physics Center Workshop “Molecule-Surface Interactions: Ele-mentary Reactive Processes”, Donostia/San Sebastian, Spain

For further information please refer to http://dipc.sw.edu.es/dipc/molecule-surface-interactions.htm