Semiclassical analysis of the associative ionisation process Na(3p)+Na(3p) to Na₂⁺+e

The AI process resulting from the collision of two Na(3p) atoms is studied semiclassically using available adiabatic and diabatic potential curves. Asymptotic force constants are evaluated for the four m a m b incident channels, and quantum defect dipole matrix elements are used. The total AI cross section is found to be within a factor of 2-3 of most measurements at the temperature extremes of 0.75 mK and 650 K, a range in which the cross section changes by a factor of 10 3 . Comparison of ratios of individual sigma (m a m b ) with measurements involving polarised atoms in colliding beams also shows qualitative agreement.