Penning ionization of H2 by He(2 3S): Quantum mechanical scattering calculations within the rigid-rotor approximation

Elastic, rotationally inelastic, and total ionization cross sections have been calculated quantum mechanically for the scattering of metastable He(2 3S) atoms by H2 in the energy range 0.010–0.500 eV. The potential surface V* and autoionization width Γ previously calculated by the authors were used. The scattering calculation was based on the Arthurs and Dalgarno formalism for the scattering of an atom by a rigid rotator. The coupled channel equations were solved numerically for the complex, angularly dependent potential V*−(i/2) Γ. The results show that the total ionization cross section σi increases sharply with energy. Hence the ionization rate constant has a strong temperature dependence. The calculated rate constants are in good agreement with the experimental results of Lindinger et al.