Benchmark calculations with correlated molecular wave functions. IX. The weakly bound complexes Ar{endash}H{sub 2} and Ar{endash}HCl

Journal Article · Sat Aug 01 04:00:00 EDT 1998 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.476510· OSTI ID:639060

Woon, D E; Peterson, K A; Dunning, Jr, T H ^[1]

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1. Theory, Modeling and Simulation, Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352 (United States)

The interaction of Ar with H{sub 2} and HCl has been studied using Mo/ller{endash}Plesset perturbation theory (MP2, MP3, MP4) and coupled-cluster [CCSD, CCSD(T)] methods with augmented correlation consistent basis sets. Basis sets as large as triply augmented quadruple zeta quality were used to investigate the convergence trends. Interaction energies were determined using the supermolecule approach with the counterpoise correction to account for basis set superposition error. Comparison with the available empirical potentials finds excellent agreement for both binding energies and transition state. For Ar{endash}H{sub 2}, the estimated complete basis set (CBS) limits for the binding energies of the two equivalent minima and the connecting transition state (TS) are, respectively, 55 and 47thinspcm{sup {minus}1} at the MP4 level and 54 and 46thinspcm{sup {minus}1} at the CCSD(T) level, respectively [the XC(fit) empirical potential of Bissonnette {ital et al.} [J. Chem. Phys. {bold 105}, 2639 (1996)] yields 56.6 and 47.8thinspcm{sup {minus}1} for H{sub 2} (v=0)]. The estimated CBS limits for the binding energies of the two minima and transition state of Ar{endash}HCl are 185, 155, and 109thinspcm{sup {minus}1} at the MP4 level and 176, 147, and 105thinspcm{sup {minus}1} at the CCSD(T) level, respectively [the H6(4,3,0) empirical potential of Hutson [J. Phys. Chem. {bold 96}, 4237 (1992)] yields 176.0, 148.3, and 103.3thinspcm{sup {minus}1} for HCl (v=0)]. Basis sets containing diffuse functions of (dfg) symmetries were found to be essential for accurately modeling these two complexes, which are largely bound by dispersion and induction forces. Highly correlated wave functions were also required for accurate results. This was found to be particularly true for ArHCl, where significant differences in calculated binding energies were observed between MP2, MP4, and CCSD(T). {copyright} {ital 1998 American Institute of Physics.}

• OSTI ID: 639060
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 6 Vol. 109; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ARGON COMPLEXES
BINDING ENERGY
ELECTRON CORRELATION
ELECTRONIC STRUCTURE
HYDROCHLORIC ACID
HYDROGEN COMPLEXES
INTERMOLECULAR FORCES
PERTURBATION THEORY
WAVE FUNCTIONS