WKB approximation for the reaction-path Hamiltonian: Application to variational transition state theory, vibrationally adiabatic excited-state barrier heights, and resonance calculations

Journal Article · Sun Jul 01 04:00:00 EDT 1984 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.447386· OSTI ID:6676239

Garrett, B C; Truhlar, D G

We present several kinds of calculations, for reaction rates, vibrationally adiabatic barrier heights, and resonance energies and widths, in which we use the WKB approximation for vibrational energies of stretches in the reaction-path Hamiltonian. We consider both collinear and three-dimensional atom-transfer reactions. As compared to previous calculations employing the Morse approximation for vibrational energies of stretches, there is generally significant quantitative improvement in accuracy for ground-state quantities and thermal reaction rates, and there is dramatic improvement in accuracy for excited-state quantities. We also update our predictions for some three-dimensional reaction rates calculated with an accurate ab initio potential energy surface.

• Research Organization: Chemical Dynamics Corporation, Columbus, Ohio 43220
• OSTI ID: 6676239
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 81:1; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
CHEMICAL REACTION KINETICS
CONFORMATIONAL CHANGES
ENERGY LEVELS
EXCITED STATES
KINETICS
LEVEL WIDTHS
REACTION KINETICS
VARIATIONAL METHODS
VIBRATIONAL STATES
WKB APPROXIMATION