Quantum enhancement of vibrational predissociation near the dissociation threshold

Journal Article · Thu Jan 01 04:00:00 EST 2004 · Physical Review. A

DOI:https://doi.org/10.1103/PhysRevA.69.012704· OSTI ID:20640606

Cote, R ^[1]; Dashevskaya, E I ^[2]; Nikitin, E E ^[2]; Troe, J ^[3]

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1. Physics Department, University of Connecticut, Storrs, Connecticut 06269-3046 (United States)
2. Department of Chemistry, Technion-Israel Institute of Technology, Haifa, 32000 (Israel)
3. Institut fuer Physikalische Chemie der Universitaet Goettingen, Tammannstrasse 6, D-37077 Goettingen (Germany)

We discuss quantum enhancement of the quasiclassical vibrational predissociation (VP) rate of an atom (A)-diatom (BC) van der Waals (vdW) complex A-BC from a state lying close to the dissociation threshold. The enhancement is due to the accumulation of a noticeable fraction of the state population near the outer turning point of the A-BC bond. For potentials behaving as power-laws at large separations, the enhancement manifests itself in the variation of the energy dependence of the VP frequency factor from the classical frequency to its quantum counterpart. We show that it is related to the complex scattering length associated with the vibrational relaxation of BC in collisions with A. We also discuss the corrected quasiclassical quantization condition for energy levels of a diatom lying very close to the dissociation threshold. Our results generalize those of J. Trost, C. Eltshka, and H. Friedrich [J. Phys. B 31, 361 (1998)] and C. Boisseau et al. [Eur. Phys. J. D 12, 199 (2000)] for the calculation of complex energy levels of an anharmonic oscillator that dissociates from highly excited states under the action of a weak high-frequency perturbation.

• OSTI ID: 20640606
• Journal Information: Physical Review. A, Journal Name: Physical Review. A Journal Issue: 1 Vol. 69; ISSN 1050-2947; ISSN PLRAAN
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANHARMONIC OSCILLATORS
ATOM COLLISIONS
ATOMS
DIATOMS
DISTURBANCES
ENERGY DEPENDENCE
ENERGY TRANSFER
EXCITED STATES
POTENTIALS
PREDISSOCIATION
QUANTIZATION
RELAXATION
SCATTERING LENGTHS
VAN DER WAALS FORCES
VARIATIONS
WKB APPROXIMATION