Direct ab initio dynamics study on the hydrogen abstraction reaction of CH₃CCl₃ + OH → CH₂CCl₃ + H ₂O

The ab initio direct dynamics approach is employed to study the hydrogen abstraction reaction of CH₃CCl₃ + OH. The potential energy surface (PES) information is obtained at the MP2/6-311G(d,p) and G3(MP2) (single-point) levels of theory. A hydrogen-bonded complex is located in the reactant channel. Dynamics calculations are performed by variational transition-state theory with the interpolated single-point energy approach (VTST-ISPE). Canonical variational transition-state theory and a small curvature tunneling correction are included to calculate the rate constants within 200-2000 K. Both theoretical rate constants and activation energy are in good agreement with experimental ones over the measured temperature range, 222-761 K. The calculations show that the variational effect is small and the tunneling effect is significant in the lower temperature range.