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Ab initio potentials for weakly interacting systems: Homonuclear rare gas dimers
Author(s) -
Laschuk Eduardo F.,
Martins Márcio M.,
Evangelisti Stefano
Publication year - 2003
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.10738
Subject(s) - homonuclear molecule , rotational–vibrational spectroscopy , counterpoise , ab initio , chemistry , extrapolation , basis set , ab initio quantum chemistry methods , atomic physics , computational chemistry , physics , excited state , molecule , density functional theory , mathematics , statistics , organic chemistry
A series of high‐level ab initio interatomic potentials for the homonuclear rare gas dimers He 2 , Ne 2 , and Ar 2 is presented, with predictions of rovibrational spectroscopic parameters and second virial coefficients. These potentials were created by using d‐aug‐cc‐pV n Z, n = D,T,Q basis sets, MP4 and CCSD(T) correlation energy treatments, the counterpoise correction to the basis set superposition error, and extrapolation schemes for estimating complete basis set (CBS) limits. A careful FCI correction was added to our best He 2 CCSD(T) potential. The characteristic parameters D e , R e , k , and σ of the ab initio potentials were compared with those of reliable empirical and ab initio potentials. Our best results for He 2 recovered 99.9% of Janzen's SAPT2 well depth Janzen, A.R.; Aziz, R.A. J Chem Phys 1997, 107, 914–919. In the case of Ar 2 , we recovered 99.8% of Aziz's HFDID1 well depth Aziz, R.A. J Chem Phys 1993, 99, 4518–4525. For neon, second virial coefficients typically came to within 0.5–1.0 cm 3 mol −1 of experimental values and rovibrational energy levels exhibited errors of about 1.4 cm −1 . Our best argon results exhibited second virial coefficients in agreement of 0.25 cm 3 mol −1 with experiment and rovibrational energy level errors around 0.2 cm −1 . © 2003 Wiley Periodicals, Inc. Int J Quantum Chem 95: 303–312, 2003