Nonadditive intermolecular forces from the spectroscopy of van der Waals trimers: A theoretical study of Ar[sub 2]-HF

Journal Article · Sun Jan 01 04:00:00 EST 1995 · Physical Review A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.51.239· OSTI ID:6713828

Ernesti, A; Hutson, J M ^[1]

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1. Department of Chemistry, University of Durham, South Road, Durham, DH13LE (United Kingdom)

Calculations of vibrational energies and rotational constants are carried out for the van der Waals trimer Ar[sub 2]-HF. The calculations include all five intermolecular degrees of freedom. The different intramolecular vibrational states [ital v] of the HF molecule are separated out adiabatically, so that the calculations are carried out on effective intermolecular potentials for each HF vibrational state separately. Calculations are performed both on pairwise-additive potentials, derived from the well-known Ar-Ar and Ar-HF potentials, and on nonadditive potentials, incorporating various different contributions to the three-body forces. The results are compared with experimental results from high-resolution spectroscopy, and provide detailed information on the anisotropy of the nonadditive intermolecular forces. As in previous work on Ar[sub 2]-HCl, it is found that a very important nonadditive term arises from the interaction between the permanent multipoles of the HF molecule and the exchange quadrupole caused by distortion of the two Ar atoms as they overlap. An improved model of this term is described.

• OSTI ID: 6713828
• Journal Information: Physical Review A; (United States), Journal Name: Physical Review A; (United States) Vol. 51:1; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

664100* -- Theory of Electronic Structure of Atoms & Molecules-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ARGON COMPOUNDS
CHLORINE COMPOUNDS
ENERGY
ENERGY LEVELS
EXCITED STATES
FLUORINE COMPOUNDS
HALOGEN COMPOUNDS
HYDROGEN COMPOUNDS
INTERMOLECULAR FORCES
MANY-BODY PROBLEM
POTENTIAL ENERGY
RARE GAS COMPOUNDS
ROTATIONAL STATES
SPECTROSCOPY
THREE-BODY PROBLEM
VAN DER WAALS FORCES
VIBRATIONAL STATES