Sudden rotation calculations of atom–molecule scattering

Abstract

Rotational inelastic cross sections for two atom–rigid rotor systems, ⁴He+H₂(j) and ⁴He+I₂* (j), have been calculated using a quantal sudden approximation that we term the sudden rotation approximation. Vibrational inelastic cross sections have also been calculated for ⁴He+H₂(ν,j) using a two and three vibration basis set for total energies between 1.2 and 4.2 eV. The present results for ⁴He+H₂ are compared with the coupled channel and coupled states results of McGuire and Kouri and with the two vibration results of McGuire. The ⁴He+I₂* results are compared with quasiclassical trajectory calculations and the experiments of Steinfeld and co‐workers.