Calculations of autoionization rates for double-Auger decay of multiply-excited states in nitrogen

The authors consider the probability for double-Auger decay of multiply-excited states in N n+ with two 1s vacancies. They have calculated the branching ratio R 3 between the double-Auger decay filling both holes in the 1s shell and the normal Auger decay for initial 2p N , 2s2p N-1 and 2s 2 2p N-2 configurations with N=3, 4, 5 and 6. They show that R 3 depends more strongly on the number of 2s electrons than on the total number of electrons in the n=2 shells. They find that the 'shake-down' of a 2s electron due to the non-orthogonality between the initial 2s and the final 1s electron is the most important effect. Comparison with the result of recent studies of neutralization of slow highly-excited ions at surfaces suggests the presence of one or two 2s electrons in the ion at the time of the double-Auger decay.