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Title: Ab Initio and Analytic Intermolecular Potentials for Ar–CH3OH

Abstract

Ab initio calculations at the CCSD(T)/aug-cc-pVTZ level of theory were used to characterize the Ar–CH₃y6tOH intermolecular potential energy surface (PES). Potential energy curves were calculated for four different Ar + CH₃OH orientations and used to derive an analytic function for the intermolecular PES. A sum of Ar–C, Ar–O, Ar–H(C), and Ar–H(O) two-body potentials gives an excellent fit to these potential energy curves up to 100 kcal mol¯¹, and adding an additional r¯¹n term to the Buckingham two-body potential results in only a minor improvement in the fit. Three Ar–CH₃OH van der Waals minima were found from the CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ calculations. The structure of the global minimum is in overall good agreement with experiment (X.-C. Tan, L. Sun and R. L. Kuczkowski, J. Mol. Spectrosc., 1995, 171, 248). It is T-shaped with the hydroxyl H-atom syn with respect to Ar. Extrapolated to the complete basis set (CBS) limit, the global minimum has a well depth of 0.72 kcal mol¯¹ with basis set superposition error (BSSE) correction. The aug-cc-pVTZ basis set gives a well depth only 0.10 kcal mol¯¹ smaller than this value. The well depths of the other two minima are within 0.16 kcal mol¯¹ of the global minimum. The analytic Ar–CH₃OHmore » intermolecular potential also identifies these three minima as the only van der Waals minima and the structures predicted by the analytic potential are similar to the ab initio structures. The analytic potential identifies the same global minimum and the predicted well depths for the minima are within 0.05 kcal mol¯1 of the ab initio values. Combining this Ar–CH₃OH intermolecular potential with a potential for a OH-terminated alkylthiolate self-assembled monolayer surface (i.e., HO-SAM) provides a potential to model Ar + HO-SAM collisions.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
921849
Report Number(s):
PNNL-SA-53749
3566; KP1303000; TRN: US200802%%934
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Chemistry Chemical Physics. PCCP, 8(40):4678-4684; Journal Volume: 8; Journal Issue: 40
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANALYTIC FUNCTIONS; POTENTIAL ENERGY; ARGON; METHANOL; INTERMOLECULAR FORCES; Environmental Molecular Sciences Laboratory

Citation Formats

Tasic, Uros, Alexeev, Yuri, Vayner, Grigoriy, Crawford, T Daniel, Windus, Theresa L., and Hase, William L. Ab Initio and Analytic Intermolecular Potentials for Ar–CH3OH. United States: N. p., 2006. Web. doi:10.1039/b609743j.
Tasic, Uros, Alexeev, Yuri, Vayner, Grigoriy, Crawford, T Daniel, Windus, Theresa L., & Hase, William L. Ab Initio and Analytic Intermolecular Potentials for Ar–CH3OH. United States. doi:10.1039/b609743j.
Tasic, Uros, Alexeev, Yuri, Vayner, Grigoriy, Crawford, T Daniel, Windus, Theresa L., and Hase, William L. Wed . "Ab Initio and Analytic Intermolecular Potentials for Ar–CH3OH". United States. doi:10.1039/b609743j.
@article{osti_921849,
title = {Ab Initio and Analytic Intermolecular Potentials for Ar–CH3OH},
author = {Tasic, Uros and Alexeev, Yuri and Vayner, Grigoriy and Crawford, T Daniel and Windus, Theresa L. and Hase, William L.},
abstractNote = {Ab initio calculations at the CCSD(T)/aug-cc-pVTZ level of theory were used to characterize the Ar–CH₃y6tOH intermolecular potential energy surface (PES). Potential energy curves were calculated for four different Ar + CH₃OH orientations and used to derive an analytic function for the intermolecular PES. A sum of Ar–C, Ar–O, Ar–H(C), and Ar–H(O) two-body potentials gives an excellent fit to these potential energy curves up to 100 kcal mol¯¹, and adding an additional r¯¹n term to the Buckingham two-body potential results in only a minor improvement in the fit. Three Ar–CH₃OH van der Waals minima were found from the CCSD(T)/aug-cc-pVTZ//MP2/aug-cc-pVTZ calculations. The structure of the global minimum is in overall good agreement with experiment (X.-C. Tan, L. Sun and R. L. Kuczkowski, J. Mol. Spectrosc., 1995, 171, 248). It is T-shaped with the hydroxyl H-atom syn with respect to Ar. Extrapolated to the complete basis set (CBS) limit, the global minimum has a well depth of 0.72 kcal mol¯¹ with basis set superposition error (BSSE) correction. The aug-cc-pVTZ basis set gives a well depth only 0.10 kcal mol¯¹ smaller than this value. The well depths of the other two minima are within 0.16 kcal mol¯¹ of the global minimum. The analytic Ar–CH₃OH intermolecular potential also identifies these three minima as the only van der Waals minima and the structures predicted by the analytic potential are similar to the ab initio structures. The analytic potential identifies the same global minimum and the predicted well depths for the minima are within 0.05 kcal mol¯1 of the ab initio values. Combining this Ar–CH₃OH intermolecular potential with a potential for a OH-terminated alkylthiolate self-assembled monolayer surface (i.e., HO-SAM) provides a potential to model Ar + HO-SAM collisions.},
doi = {10.1039/b609743j},
journal = {Physical Chemistry Chemical Physics. PCCP, 8(40):4678-4684},
number = 40,
volume = 8,
place = {United States},
year = {Wed Sep 20 00:00:00 EDT 2006},
month = {Wed Sep 20 00:00:00 EDT 2006}
}