Strong electron correlation in Ca 2p, Sr 3d and Ba 4d core hole states investigated by means of photoelectron spectroscopy and MCDF calculations

Abstract

Many-electron (correlation) effects play a dominant role in inner-shell ionization processes in free alkaline earth metal atoms. In this work calcium 2p, strontium 3d and barium 4d photoionization processes have been investigated with emphasis on the correlation effects. In order to understand the details of the spectra, a series of ab initio calculations based on multiconfiguration Dirac–Fock method have been performed. Theoretical predictions are compared with high-resolution synchrotron radiation induced electron spectra and the capability of the multiconfigurational computations in reproducing the experiment is discussed.