Meng Huang and Anne B. McCoy Department of Chemistry and Biochemistry The Ohio State Univerisity.
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Transcript of Meng Huang and Anne B. McCoy Department of Chemistry and Biochemistry The Ohio State Univerisity.
Vibrational Analysis of Hydrated Halide Clusters Spectra
Meng Huang and Anne B. McCoyDepartment of Chemistry and BiochemistryThe Ohio State Univerisity
IntroductionHydrated Halide Clusters
Provide good model for studying the interactions between ions and molecules such as intramolecular hydrogen-bonding
May provide explanations to important processes such as the transport of ions through membranesImportant clusters in aqueous chemistry
Assignment to the experimental spectrum taken by argon predissociation spectra[1]
[1] Horvath. S., McCoy, A. B., Elliot, B. M.,Weddle, G. H., Roscioli, J. R., and Johnson, M. A., J. Phys. Chem. A, 114, 1556–1568 (2010).
1000 1200 1400 1600 1800 3000 3200 3400 3600 3800
Photon Energy, cm-1
1
2
3
4
5 6
7
9
10
11
12
131415
1617
188
MotivationI-(H2O) Argon Predissociation Spectra [1]
Peak Position, cm-1
1 (2noop) 1098.32 1115.53 1141.9
4 (nHOH) 1639.35 (nHOH+nip) 1799.06 (nHOH+nip) 1890.2
7 (2nHOH) 3245.88 (2nHOH+nOX) 3367.1
9 (nOHb) 3392.810 (nOHb) 3422.2
11 3475.012 (nOHb+nOX) 3524.213 (nOHb+nOX) 3552.1
14 3625.815 3648.9
16 (nOHf) 3691.917 (nOHf) 3705.6
18 3765.1
[1] Horvath. S., McCoy, A. B., Elliot, B. M.,Weddle, G. H., Roscioli, J. R., and Johnson, M. A., J. Phys. Chem. A, 114, 1556–1568 (2010).
Molecular Geometry
𝜈𝑂𝐻 𝑏
Equilibrium Transition State𝜈𝑂𝐻 𝑓
𝜃ipx
y 𝜈as𝜈s
𝜈ip
𝜃ip=0𝜈ip
Reduced Dimensional AnalysisHamiltonian and Dipole Moment
𝜇𝑖 (𝜃 𝑖𝑝)=𝜇𝑖 ,0 (𝜃𝑖𝑝 )+𝜕𝜇𝑖
𝜕∆𝑟1(𝜃 𝑖𝑝) ∆𝑟 1+
𝜕𝜇𝑖
𝜕∆𝑟 2(𝜃𝑖𝑝 ) ∆𝑟2
ħ=1
Reduced Dimensional AnalysisTheoretical Details
Potential Energy Surface/Force Constantsab initio calculation with MP2/aug-cc-pVTZ-(PP) level of theory
Dipole Moment/First order Dipole Derivativeab initio calculation with MP2/aug-cc-pVTZ-(PP) level of theory
Basis Sets for Linear Variation Calculation Stretch Mode : Harmonic OscillatorIn-plane Bend : Grid Basis Set (DVR)
Simulation of SpectraLorentzian (FWHM = 5 cm-1)
I-(H2O)/I-(D2O) Spectra
3400 3500 3600 3700 3800 3900 4000
Wavenumber
I-(H2O) Simulation
3200 3300 3400 3500 3600 3700 3800
I-(H2O) Experiment
2400 2500 2600 2700 2800 2900
Wavenumber
I-(D2O) Simulation
2300 2400 2500 2600 2700 2800
I-(D2O) ExperimentνOHb
νOHb+ νOX
νOHb+ νip
νOHf2νHOH
νOHb
νOHfνOHb+ νip
νODb
νODb+ νip
νODf
νODf
νODb
2νDOD
3400 3500 3600 3700 3800 3900 4000
Wavenumber
3200 3300 3400 3500 3600 3700 3800
Combination Band νOHb
+ νip
Stretch – Bending Coupling
-120 -90 -60 -30 0 30 60 90 120
3500
3600
3700
3800
3900
4000
Fre
quen
cy (
cm-1)
ip
Normal Mode Frequencies of O-H Stretch Modes in I-(H2O)
-90 -60 -30 0 30 60 900
200
400
600
800
1000
Ene
rgy
(cm
-1)
ip
Potential energy surface and energy levels of the in-plane bending mode for I-(H2O)
Tunneling Splitting
-90 -60 -30 0 30 60 904500
5000
5500
12000
12500
13000
13500
Effe
ctiv
e E
ne
rgy
(cm
-1
)
ip
Combination Band νOHb+ νip
The increase of the barrier height leads to the overlap between ground state wavefunction and bending excited state. The tunneling splitting also decreases dramatically from ground state to excited state.
νOHb=1
νOHb=0
νip=1
νip=0
νip=0
νOHb νOHb + νip
Spectra of X-(H2O)
3200 3400 3600 3800 4000
Wavenumber
3200 3400 3600 3800 4000
3200 3400 3600 3800 4000
3000 3200 3400 3600 3800
Wavenumber
3000 3200 3400 3600 3800
3000 3200 3400 3600 3800
Experimental Spectrum of X-(H2O) Calculated Spectrum of X-(H2O)
νOHb
νOHb
νOHb
νOHb
νOHb
νOHb
νOHf
νOHf
νOHf
νOHf
νOHf
νOHf
νOHb+ νip
νOHb+ νip
νOHb+ νip
νOHb+ νip
νOHb+ νip
νOHb+ νip2νHOH
2νHOH
2νHOH
Cl-(H2O) Cl-(H2O)
Br-(H2O)
I-(H2O)
Br-(H2O)
l-(H2O)
3000 3200 3400 3600 3800
Wavenumber
3000 3200 3400 3600 3800
3000 3200 3400 3600 3800
Spectra of X-(D2O)
2300 2400 2500 2600 2700 2800 2900
Wavenumber
2300 2400 2500 2600 2700 2800 2900
2300 2400 2500 2600 2700 2800 2900
2400 2500 2600 2700 2800 2900 3000
Wavenumber
2400 2500 2600 2700 2800 2900 3000
2400 2500 2600 2700 2800 2900 3000
Experimental Spectrum of X-(D2O) Calculated Spectrum of X-(D2O)
Cl-(D2O) Cl-(D2O)
Br-(D2O) Br-(D2O)
I-(D2O) I-(D2O)
νODf
νODf
νODf
νODf
νODf
νODf
νODb
νODb
νODb
νODb
νODb
νODb
2νDOD
2νDOD
2νDOD νODb+ νip
νODb+ νip
νODb+ νip
Comparison among Different Hydrated Halide Clusters
-90 -60 -30 0 30 60 901000
1500
2000
2500
3000
3500
4000
V0+
ZP
E (
cm-1)
ip
Cl-(H2O)
Br-(H2O)
I-(H2O)
509 cm-1
402 cm-1
208 cm-1
The comparison among different calculated hydrated halide clusters spectra provides expected result.
SummaryReduced dimensional analysis show qualitative agreement with the experimental spectrum
Doublet structure in the O-H stretch transition is attributed to the double well potential in in-plane bending modeOne transition is assigned to be combination band of O-H stretch and in - plane bending mode Comparison among calculated spectra of different hydrated halide clusters also show the expected result
AcknowledgementDr. Anne B. McCoy
Andrew Petit
Zhou Lin
Bernice Opoku-
Agyeman
Laura Dzugan
Bethany Wellen
Jason Ford
Thank you!