NONPERTURBATIVE TIME-DEPENDENT THEORY OF TWO-ELECTRON ATOMS IN STRONG LASER FIELDS

This work deals with the fundamental problem of the behavior of the two-electron atom under intense laser fields. We present a broad scope of calculations and results and, we believe, the first ATI spectrum, in He and Mg atom, beyond the single active electron model in a fully time-dependent nonperturbative calculation. For He, we perform calculations both on a two-electron basis with configuration interaction where both electrons are allowed to be excited, and on a frozen core basis. The comparison is a direct measure of the effect of correlation under strong fields. The results for Mg shows that the method also opens a way to the study of atoms with much stronger electron correlation in intense laser fields.