K-shell photoionization of beryllium

The numerical multiconfiguration Hartree-Fock method is used to study in detail the photoionization of atomic beryllium near the 1s threshold. Electron correlation effects, which are found to be very important in the K-shell partial photoionization cross section, have been taken into account very accurately through the configuration-interaction procedure. The present results are compared with experimental measurements of the relative contributions of the three major ionization channels and are found to be in excellent agreement. The existence of the principal resonances reported by the experiment has been confirmed and assignments made to these contributions based on accurate energy calculations