Electronic correlation in the shake-up process in atomic doubly excited asymmetric states

The effects of the electronic correlation in the shake-up process of atomic doubly excited asymmetric states have been investigated by using a nondegenerate perturbative method. It is shown that the overlap spectrum and the recently observed abnormal spectrum can be described by the same theoretical framework. The quantitative intrinsic relation between the well known overlap formula and the electronic correlation has been revealed analytically. The scope for applying the overlap formula has been discussed. The shake-off process has also been discussed as a continuum case of the shake-up process. It is shown that the escape electron in a shake-off process of a higher-l state or with a higher escape energy tends to increase its angular momentum.