Photoionization of 1s Electron and Corresponding Shake-Up Process in Ground and Excited Lithium Atoms

Abstract

The cross sections of the Is electron photoionization and corresponding shake-up processes for Li atoms in the ground state Is2 2s and excited states 1s2 2p, 1s2 3s, 1s2 3p and 1s2 3d are calculated using the multi-configuration Dirac-Fock method. The latest experimental photoelectron spectrum at hv = 100 eV [Cubaynes D et al. Phys. Rev. Lett. 99 (2007) 213004] has been reproduced by the present theoretical investigation excellently. The relative intensity of the shake-up satellites shows that the effects of correlation and relaxation become more important for the higher excited states of the lithium atom, which are explained very well by the spatial overlap of the initial and final state wavefunctions. In addition, strong dependence of the cross section on the atomic orbitals of the valence electrons are found, especially near the threshold.