title: Reduced dimensionality quantum dynamics of CH3 + CH4 --> CH4 + CH3: symmetric hydrogen exchange on an Ab initio potential.
abstract: The symmetric title reaction CH(3) + CH(4) --> CH(4) + CH(3) is studied using quantum scattering theory. Quantum dynamics calculations are performed in hyperspherical coordinates with a two-dimensional effective potential energy surface consisting of an analytical 18-parameter double Morse function fit to ab initio data at the CCSD(T)/cc-pVTZ//MP2/cc-pVTZ level of theory. Spectator modes are treated adiabatically by inclusion of projected zero-point energy corrections in the effective potential. The close-coupled equations are solved via R-matrix propagation. Energy and J-shifted thermal rate constants are compared to experimental data and highlight the importance of quantum tunneling. Oscillating reactivity and metastable bound state resonances are observed in the cumulative and state-to-state reaction probabilities. State-to-state differential and initial state-selected integral cross sections are presented and discussed. Primary and secondary kinetic isotope effects for two symmetric deuterated variants of the title reaction are also presented.
authors.affiliation: Department of Chemistry, University of Oxford, PTCL, South Parks Road, Oxford, OX13QZ, United Kingdom.
authors.forename: Sarah M
authors.initials: SM
authors.lastname: Remmert
authors.forename: Simon T
authors.initials: ST
authors.lastname: Banks
authors.forename: David C
authors.initials: DC
authors.lastname: Clary