Associative ionisation rate constants as a function of quantum numbers n and l in Na*(nl)+Na(3s) collisions for 17⩽n⩽27 and l=0, l=1 and l⩾2

The authors have determined relative associative ionisation (AI) rate constants k_AI for a series of Na(3s)+Na*(nl) collisions where 17<or=n<or=27 and l=0, l=1 and l>or=2. The relative k_AI values are scaled to earlier absolute determinations. They compare the behaviour of k_AI as a function of n and l with a rigorous application of a model suggested earlier by Janev and Mihajlov (1980). Disagreements between measured and calculated rate constants demonstrate that, even for moderately high n, the spectator Rydberg electron viewpoint for associative ionisation is not a complete picture.