Rovibrational energy transfer in collisions of H_{2} with D_{2}: a fulldimensional wave packet propagation study
Abstract
We present fulldimensional quantum dynamics calculations for the process of rovibrational energy transfer in collisions between H_{2} and D_{2} molecules, specifically H_{2}(ν = 1) + D_{2}(ν = 0) → H_{2}(ν = 0) + D_{2}(ν = 1). Rotationally resolved statetostate crosssections are obtained for collision energies up to 0.5 eV. From these we calculate rotationally averaged thermal rate coefficients in the temperature range from 100 to 500 K, and compare them with available experimental data. For some transitions, we found it numerically advantageous to compute crosssections of the reverse collision process and then use microscopic reversibility to obtain the originally sought crosssections. We employ the MultiConfiguration TimeDependent Hartree (MCTDH) method for propagating wave packets, and calculate the crosssections from transition probabilities obtained by the correlation function formalism introduced by Tannor and Weeks. Computations are performed with a potential energy surface that is based on the sixdimensional surface from Boothroyd et al. but reduced in anisotropy, as suggested by Pogrebnya and Clary. The expression of the kinetic energy operator in terms of internal curvilinear coordinates allows us to treat the kinematics of the system exactly, without any decoupling approximations.
 Publication:

Molecular Physics
 Pub Date:
 May 2012
 DOI:
 10.1080/00268976.2012.667165
 Bibcode:
 2012MolPh.110..619O
 Keywords:

 quantum molecular dynamics;
 inelastic collisions;
 crosssections;
 rate coefficients;
 hydrogen;
 deuterium