Electronic structure of atoms in laser plasmas: a Debye shielding approach

Spectral properties of the low-lying singlet states of a helium atom and those of the low-lying doublet states of a lithium atom in laser plasmas are calculated using a quantum chemical configuration interaction method with a Debye shielding model Hamiltonian. A large spherical Gaussian basis set is adopted to describe the wavefunctions of electrons bound in a non-Coulombic Yukawa-type potential with high accuracy. The relative energies and the first ionization potential are found to decrease as the shielding parameter A increases and the number of bound states to decrease gradually as mu increases. The oscillator strengths for the lowest dipole-allowed (2p) P-1-(1s) S-1 transition of He and the second lowest (3p) P-2-(2S) S-2 transitions of Li are shown to decrease as mu increases and the lowest (2p) P-2-(2S) S-2 transition of Li to increase.