Calculation of intermolecular potentials for H₂–H₂ and H₂–O₂ dimers ab initio and prediction of second virial coefficients
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Date
2015
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Publisher
Elservier
Abstract
The intermolecular interaction potentials of the dimers H₂–H₂ and H₂–O₂ were calculated
from quan-tum mechanics, using coupled-cluster theory CCSD(T) and correlation-consistent basis sets
aug- cc-pVmZ (m = 2, 3); the results were extrapolated to the basis set limit aug-cc-pV23Z. The
interaction energies were corrected for the basis set superposition error with the
counterpoise scheme. For comparison also Møller–Plesset perturbation theory (at levels 2 to 4)
with the basis sets aug-cc-pVTZ were considered, but the results proved inferior. The
quantum mechanical results were used to construct analytical pair potential functions.
From these functions the second virial coefficients of hydrogen and the cross virial
coefficients of the hydrogen–oxygen system were obtained by integration; in both
cases corrections for quantum effects were included. The results agree well with
experimental data, if available, or with empirical correlations.
Description
Keywords
Intermolecular potentials; dimers ab initio; second virial coefficients