ELECTRON TRANSLATION FACTORS IN ORIENTING CHARGE-TRANSFER COLLISIONS

The role of the electron translational factors (ETF) in the semiclassical theory of charge transfer is addressed with respect to orientation effects and possible propensity rules in s-p and p-p capture processes. It is shown that orientation effects can be understood in the light of the intuitive classical 'rolling ball' and 'velocity matching' arguments and analysed using the Larsen-Taulbjerg first-order approximation to the ETF. Emphasis is placed on investigating resonant p-p transfer which is a crucial test case for the effects of ETF on orientation dependences. The predictions are exemplified by four-state close-coupling calculations for Na(3p(m)) + Na+ --> Na+ + Na(3p'm) resonant transfer taking full account of ETF. Some problems involved in comparing experimental data at small scattering angles with theoretical predictions are discussed.