Test of variational transition state theory with a large-curvature tunneling approximation against accurate quantal reaction probabilities and rate coefficients for three collinear reactions with large reaction-path curvature: Cl+HCl, Cl+DCl, and Cl+MuCl

Journal Article · Sun May 15 04:00:00 EDT 1983 · J. Chem. Phys.; (United States)

DOI:https://doi.org/10.1063/1.444613· OSTI ID:6313654

Bondi, D K; Connor, J N.L.; Garrett, B C; Truhlar, D G

The large-curvature ground-state model for the transmission coefficient of generalized transition state theory (presented in a previous paper by B. C. Garrett, D. G. Truhlar, A. F. Wagner, and T. H. Dunning, J. Chem. Phys. 78, 4400(1983)) is tested against accurate quantal calculations of the rate coefficients for collinear reactions with very large inertial effects, namely Cl+HCl..-->..ClH+Cl, Cl+DCl..-->..ClD+Cl, and Cl+MuCl..-->..ClMu+Cl. The tests cover the temperature range 200--2400 K. The accurate rate calculations are based on reaction probabilities obtained by a new numerical method for solving Schroedinger's equation in Delves' coordinates. Improved canonical variational transition state theory predicts rate coefficients 5.0--18 times smaller than those predicted by conventional transition state theory for the H transfer; for the D transfer, the ratio is 2.0--3.4; and for Mu it is 22--2.8 x 10/sup 7/. The large-curvature model predicts transmission coefficients as large as 41, 8, and 206 for the H, D, and Mu-transfer cases at 200 K, decreasing to 1.2, 1.1, and 1.4 at 2400 K. Despite the large effect of variationally optimizing the transition state location and the large size of the tunneling effect and the wide variation of both effects with temperature, improved canonical variational transition state theory with large-curvature ground-state transmission coefficients (ICVT/LCG) is accurate within a factor of 1.7 over a temperature range of a factor of 8, 300--2400 K, for all three reactions. At 200 K, the ICVT/LCG model underestimates the rate coefficients, by factors of 2.3, 1.9, and 1.5 for H, D, and Mu, respectively.

• Research Organization: Department of Chemistry, University of Manchester, Manchester M13 9PL, England
• OSTI ID: 6313654
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 78:10; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400701 -- Radiochemistry & Nuclear Chemistry-- Hot-Atom Chemistry
CHEMICAL REACTION KINETICS
CHLORINE
ELEMENTS
HALOGENS
HIGH TEMPERATURE
HYDROCHLORIC ACID
HYDROGEN COMPOUNDS
INORGANIC ACIDS
KINETICS
LOW TEMPERATURE
MEDIUM TEMPERATURE
MESIC MOLECULES
MOLECULES
MUONIC MOLECULES
NONMETALS
REACTION KINETICS
VARIATIONAL METHODS
VERY HIGH TEMPERATURE