Nonadditive intermolecular forces from the spectroscopy of van der Waals trimers: A theoretical study of Ar[sub 2]-HF
- 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), Vol. 51:1; ISSN 1050-2947
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ARGON COMPOUNDS
INTERMOLECULAR FORCES
CHLORINE COMPOUNDS
FLUORINE COMPOUNDS
HYDROGEN COMPOUNDS
POTENTIAL ENERGY
ROTATIONAL STATES
SPECTROSCOPY
THREE-BODY PROBLEM
VAN DER WAALS FORCES
VIBRATIONAL STATES
ENERGY
ENERGY LEVELS
EXCITED STATES
HALOGEN COMPOUNDS
MANY-BODY PROBLEM
RARE GAS COMPOUNDS
664100* - Theory of Electronic Structure of Atoms & Molecules- (1992-)