Autoionizing states in beryllium-like atomic systems using explicitly correlated coordinates

A theoretical approach to obtain accurate values for autoionizing states parameters in Be-like systems is presented. The method is based on the configuration-interaction expansion of the two-active (outer) electron wavefunction in terms of correlated coordinates containing r12 explicitly and by including a model potential to represent the effect of the 1s2 core. Within our approach, 1snl core states are removed from the basis of correlated configurations by using a Phillips?Kleinman projection operator, and resonance parameters (energies and widths) are determined through the stabilization method. Illustrative examples of our implementation are given for doubly-excited states of Be and Ne6+.