Nonresonant Cross-Section, Fano-Shape Parameter and Correlation Coefficient for the Photoionization of 2s2p (1P∘) in Heliumlike

Abstract

The nonresonant cross-section, Fano-shape parameter q and coefficient parameter ρ2 have been calculated for the photoionization of helium and heliumlike under the n=2 threshold of the residual ions. Dipole matrix elements which correspond to the transitions from 1s2(S1e) to (0,1)22+ P1∘ state and from (0,1)22+ state to continuum state 1sεp (P1∘) were determined by choosing, for the ground state, the six-parameter Hylleraas wave function including electron correlation effects and a completely screened Coulomb wave function for the continuum. Energies and widths have been determined in the diagonalization method. The results are compared with available results obtained by other theoretical approaches.