ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Results of the first full-dimensional (6D) quantum calculations of the vibrational levels of the ν1 and ν2 HCl-stretch excited (HCl)2, for total angular momentum J=0, are presented. Three 6D potential energy surfaces (PESs) were employed. Two widely used PESs, the ab initio PES of Bunker and co-workers and the semiempirical PES by Elrod and Saykally, are found to give negligible tunneling splittings (≤5×10−2 cm−1) for the vibrational eigenstates of the ν1/ν2 excited (HCl)2, in sharp disagreement with the experimental tunneling splittings in the ν1 and ν2 fundamentals, −3.32 and 3.18 cm−1. In an effort to overcome this problem, a 6D electrostatic interaction potential is constructed and added to the ES1 PES; the resulting 6D PES is denoted ES1-EL. Quantum 6D calculations on the ES1-EL PES yield greatly improved tunneling splittings for ν1 (−2.31 cm−1) and ν2 (2.45 cm−1), which are 70% and 77%, respectively, of the corresponding experimental values. The ν1 and ν2 fundamental HCl-stretching frequencies calculated on the ES1-EL PES are only 5.9 cm−1 lower and 2.9 cm−1 higher, respectively, than their experimental counterparts. In addition, the quantum 6D calculations on the ES1-EL PES provide a comprehensive characterization of the ν1/ν2 supported vibrational eigenstates of (HCl)2, including their energies, assignments, and tunneling splittings. The vibration-rotation-tunneling dynamics of (HCl)2 in the ν1 and ν2 excited states which emerged from our calculations differs substantially from that observed for the HF-stretch excited (HF)2. © 1998 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.475891
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