A multichannel quantum defect approach to dissociative recombination

Abstract

The molecular multichannel quantum defect theory, initially developed to describe the escape of an electron from the molecular core region, is extended to include dissociation of the molecule into two atoms. The mixing between the two types of channels results from electronic interaction between a Rydberg series and dissociative valence states of the neutral molecule. This interaction is introduced as an additional phaseshift into the continuum parts of the wavefunctions. The resulting unified treatment of (pre)ionisation and (pre)dissociation is applied to the process of dissociative recombination, following the approach of C.M. Lee (1973). The 'indirect' process proceeding via electron capture in vibrationally excited Rydberg states is taken into account fully by the inclusion of closed electron-ion channels in the calculation. Model calculations are presented and the influence of various physical parameters on the dissociative recombination profile is tested.