TY - JOUR
T1 - 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
T2 - Cl+HCl, Cl+DCl, and Cl+MuCl
AU - Bondi, D. K.
AU - Connor, J. N.L.
AU - Garrett, Bruce C.
AU - Truhlar, Donald G.
PY - 1982
Y1 - 1982
N2 - 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 Schrödinger'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 × 107. 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.
AB - 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 Schrödinger'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 × 107. 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.
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U2 - 10.1063/1.444613
DO - 10.1063/1.444613
M3 - Article
AN - SCOPUS:36749108620
SN - 0021-9606
VL - 78
SP - 5981
EP - 5989
JO - The Journal of chemical physics
JF - The Journal of chemical physics
IS - 10
ER -