Reduced dimensionality spin-orbit dynamics of CH3 + HCl $\rightleftharpoons$⇌ CH4 + Cl on ab initio surfaces
Abstract
A reduced dimensionality quantum scattering method is extended to the study of spin-orbit nonadiabatic transitions in the CH3 + HCl $\rightleftharpoons$⇌ CH4 + Cl(2PJ) reaction. Three two-dimensional potential energy surfaces are developed by fitting a 29 parameter double-Morse function to CCSD(T)/IB//MP2/cc-pV(T+d)Z-dk ab initio data; interaction between surfaces is described by geometry-dependent spin-orbit coupling functions fit to MCSCF/cc-pV(T+d)Z-dk ab initio data. Spectator modes are treated adiabatically via inclusion of curvilinear projected frequencies. The total scattering wave function is expanded in a vibronic basis set and close-coupled equations are solved via R-matrix propagation. Ground state thermal rate constants for forward and reverse reactions agree well with experiment. Multi-surface reaction probabilities, integral cross sections, and initial-state selected branching ratios all highlight the importance of vibrational energy in mediating nonadiabatic transition. Electronically excited state dynamics are seen to play a small but significant role as consistent with experimental conclusions.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 26, 2011
- Source ID
- 10.1063/1.3592732
Entities
People
- Andrew Orr-Ewing
- David C. Clary
- Jeremy N. Harvey
- Sarah M. Remmert
- Simon T. Banks
Organizations
- Office of Naval Research
- University College London
- University of Bristol
- University of Oxford