Ab initio Calculations and Rate Constant for the Reaction H + H_2

摘要

Different levels of ab initio theory are used to calculate geometries,vibrational frequencies and energies for stationary points on the H + H_2 -> H_2 + H reaction.Frequencies and geometries calculated for H_2 at the QCISD/cc-PVTZ and QCISD/aug-cc-PVTZ levels of theory are in very good agreement with experiment.The ab initio frequencies and geometries for the transition state are similar to those for the Liu-Siegbahn-Truhlar-Horowitz and double many-body expansion surfaces.Based on these ab initio calculations,thermal rate constants are calculated for the reaction H + H_2 -> H_2 + H using the conventional transition state theory,thermo-dynamic formulation of transition state theory and semi-classical transition state theory.