Materials Science Beamline OSU, Columbus, June 21-25, 2010 SOFT X-RAY SPECTROSCOPY OF GLYCYL-GLYCINE...

Materials Science Beamline

OSU, Columbus, June 21-25, 2010

SOFT X-RAY SPECTROSCOPY SOFT X-RAY SPECTROSCOPY OF GLYCYL-GLYCINE OF GLYCYL-GLYCINE

ADSORBED ON Cu(110) ADSORBED ON Cu(110) SURFACESURFACE

Sincrotrone Trieste, Sincrotrone Trieste, Basovizza (Trieste), ItalyBasovizza (Trieste), Italy

Victor LyamayevVictor Lyamayev



Biomolecule-metal interfaceBiomolecule-metal interface

Fundamental for many Fundamental for many

fieldsfieldsBio sensors, biocompatibility of implantsBio sensors, biocompatibility of implants

Origin of lifeOrigin of life




Why synchrotron Why synchrotron radiation?radiation?• broad energy rangebroad energy range ((2222--8800 eV)00 eV) www.elettra.trieste.itwww.elettra.trieste.it

• high resolving powerhigh resolving power (2000-4000)(2000-4000)

• high high fluxflux (3x10(3x1088-3x10-3x1010 10 photons/s)photons/s)

• linearly polarized linearly polarized (>90%)(>90%)



X-ray PX-ray Photoehotoelectron lectron SSpecpectroscopy (XPS)troscopy (XPS)

XPS peaks are shifted due to different chemical state

of the atom (“chemical shift”)



Near Edge X-ray Absorption Near Edge X-ray Absorption Fine Structure (NEXAFS)Fine Structure (NEXAFS)

Probing empty MOProbing empty MO



DFT model of Gly-Glyon the Cu(110) surface

Density Functional Theory Density Functional Theory (DFT)(DFT)

Glycyl-Glycine (Gly-Gly)



Calculated adsorption geometries of Gly-Gly on Cu(110)



C 1s XPS spectra: experiment (points),theory (solid lines)

Inte

nsity

(ar

b. u

nits

)

294 292 290 288 286 284 282

Binding energy (eV)

C 1s

1.4 ML

1 ML

AN2

ZW2

ZW4

AN4297 296 295 294 293 292 291 290

Binding energy (eV)

Gas phase

Increased due tozwitterions ->



N 1s XPS spectra: experiment (points),theory (solid lines)

Inte

nsity

(ar

b. u

nits

)

406 404 402 400 398 396

Binding energy (eV)

1.4 ML

1 ML

N(1)H+

-CON(2)H-

N(1)-H...Cu

51 %3

N(1)H2

9 %

N 1s

N(1)H2-CON(2)H-91%

49 %

ZW2

AN2

ZW4

AN4408 407 406 405 404

Binding energy (eV)

Gas phase

50% ofzwitterions ->



O 1s XPS spectra: experiment (points),theory (solid lines)

Inte

nsity

(ar

b. u

nits

)

538 536 534 532 530 528 526Binding energy (eV)

1.4 ML

1 ML

O 1s

ZW2

AN2

ZW4

AN4542 541 540 539 538 537 536 535

Binding energy (eV)

Gas phase

0.1 eV broader ->



Inte

nsity

(ar

b. u

nits

)

425420415410405400395Photon energy (eV)

N

GI

NI

400.05

401.7

405.8

N K-edge NEXAFS spectra of 1 ML of Gly-Glymeasured at grazing (GI) and normal (NI) incidence

N-H bond of CONH ->

NCONH->



O K-edge NEXAFS spectra of 1 ML of Gly-Glymeasured at grazing (GI) and normal (NI) incidence

Inte

nsity

(ar

b. u

nits

)

560555550545540535530Photon energy (eV)

s_O_NI_HCflash420K_aver_sub s_O_GI_HCflash420K_aver_sub

O

GI

NI

532.7

535.7

545.0

OCONH + OCOO ->

OCOO…Cu ->



Proposed adsorption geometries of 1 ML of Gly-Gly



C 1s XPS spectra of 0.4 ML of Gly-Gly:experiment (points), theory (solid lines)

Inte

nsity

(ar

b. u

nits

)

292 290 288 286 284 282Binding energy (eV)

C(4)NC(2)N

-C(3)ONH-

C(1)OO-

C 1s

AN2a



N 1s XPS spectra of 0.4 ML of Gly-Gly:experiment (points), theory (solid lines)

Inte

nsity

(ar

b. u

nits

)

406 404 402 400 398 396 394Binding energy (eV)

-CON(2)H- N(1)-H...Cu

N 1s

AN2a

<- due to interaction via H



O 1s XPS spectra of 0.4 ML of Gly-Gly:experiment (points), theory (solid lines)

Inte

nsity

(ar

b. u

nits

)

536 534 532 530 528 526Binding energy (eV)

O 1s

AN2a



N and O K-edge NEXAFS spectra of 0.4 ML of Gly-Glymeasured at grazing (GI) and normal (NI) incidence

Inte

nsity

(ar

b. u

nits

)560555550545540535530

Photon energy (eV)

O532.7

GI

NI

535.7

545.0

Inte

nsity

(ar

b. u

nits

)

425420415410405400395

Photon energy (eV)

NI

GI

N400.05

401.7

405.8413.0



Proposed adsorption geometries of 0.4 ML of Gly-Gly



I’d like I’d like to to thank…thank…

……and thank you for your attention.and thank you for your attention.

Vitaliy FeyerVitaliy Feyer

Oksana PlekanOksana Plekan

Kevin C. PrinceKevin C. Prince

Materials Science Beamline at Materials Science Beamline at Elettra,Elettra,

Trieste, Trieste, ItalyItaly

V. CarravettaV. Carravetta Institute of Chemical Physical Institute of Chemical Physical Processes, Pisa, ItalyProcesses, Pisa, Italy

Materials Science Beamline OSU, Columbus, June 21-25, 2010 SOFT X-RAY SPECTROSCOPY OF GLYCYL-GLYCINE...

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