Accurate body frame approximations for rotationally inelastic Li⁺/H₂ scattering

Abstract

A hierarchy of body frame (BF) partitioning approximations for rotationally inelastic scattering are formulated and applied to the Li⁺/H₂ system at a total energy of 0·5 eV. For a given transition, approximations may be chosen which yield accurate S-matrix elements and thus accurate values for all cross sections. In general, the larger the quantum numbers involved in the transition, the larger the basis set required. Accurate integral cross sections are obtained using smaller basis sets. Calculations using a basis set of comparable size to an l-dominant basis give significantly better results than the latter for 0-j integral and differential cross sections. Implications of this work for the dynamics of Li⁺/H₂ collisions and application of the BF approximations to other systems are discussed.