Autodetachment of the nsnp24P1/2states in negative ions

The purpose of this work is to compute the autodetachment rates of the nsnp 2 4 P 1/2 levels for Be (2s2p 2 ), Mg (3s3p 2 ) and Ca - (4s4p 2 ). Fano's configuration interaction model is implemented to compute the interaction between the discrete and continuum spaces of the wavefunction, which are determined using the multiconfiguration Hartree-Fock technique. Analysing the decay mechanism of the 4 P 1/2 components, the authors find large cancellation effects in the transition matrix for the interaction between the discrete perturbers and the ns 2 ks 2 S 1/2 continuum channels, which makes the calculations very sensitive to computational details. They predict relatively long-lived metastable states with lifetimes in the range 10 -5 -10 -7 s, which, however, only for Be - remain in a qualitative agreement with the experiment.