ALIGNMENT AND ORIENTATION FOR CHARGE-EXCHANGE IN LI+-NA(3S, 3P) COLLISIONS .1. DIFFERENTIAL AND TOTAL CROSS-SECTIONS

The alignment and orientation effects for charge exchange in 1-1.5 keV Li+-Na(3s, 3p) collisions are studied by semiclassical close-coupling calculations employing adiabatic molecular data and a common electron translation factor. The differential cross sections from Na(3s) to Li(2s) and Li(2p) are compared to experiment, a large orientation effect is predicted for charge exchange to Li(2p(+/-1)). From Na(3p) the charge exchange is important only to the Li(2p) channel, the corresponding alignment and orientation effects are calculated. The orientation effect follows the propensity rules. The formulae for total and differential cross sections for a transition from aligned p to p state or from oriented p to p state are derived. Two differential total cross sections for oriented p(+/-1) to p(+/-1) states can be defined, the same for aligned p+/-45 degrees to p+/-45 degrees states. The important role of the translation factor is discussed and a four state model is able to describe charge exchange from Na(3p) to Li(2p) at large impact parameters.