A quantum scattering theoretical study on the reaction cross sections of ion-pair formation processes

In this paper Mille's S - matrix variational approach has been extended to study the reaction dynamics for ion - pair formation processes. M + X-2 --> M+ + X-2(-) reaction system involves two potential energy surfaces, i.e., the covalence state (M + X-2) and the ionic state (M+ + X-2(-)) and their crossing effect. The working equations for calculating ion - pair formation cross section have been derivated based on the above two - state model. The translational wavefunctions have been expanded by distributed Gaussian basis sets in calculation of matrix elements. Satisfactory results of numerical calculations using S - matix variational approach for Cs + O-2 --> Cs+ + O-2(-) ion - pair formation system have been obtained.