DENSITY-FUNCTIONAL CALCULATIONS ON TRIPLY EXCITED-STATES OF LITHIUM ISOELECTRONIC SEQUENCE

Triply excited states of many-electron atomic systems are characterize d by the presence of strong electron correlation, closeness to more th an one threshold, and degeneracy with many continua; therefore, they o ffer unusual challenges to theoretical methodologies. In the present a rticle, we computed with reasonable accuracy all the n = 2 intrashell triply excited states (2s(2)2p(2)P; 2s2p(2 2)D, P-4, P-2, S-2; and 2p( 3 2)D, P-2, S-4) of three-electron atomic systems (Z = 2, 3, 4, 6, 8, 10) by using a density functional formalism developed recently in our laboratory, based on the nonvariational Harbola-Sahni exchange potenti al in conjunction with a parametrized local Wigner and Lee-Yang-Parr c orrelation potentials. Nonrelativistic energies and densities are obta ined by solving a Kohn-Sham-type differential equation. The calculated results are compared with available experimental and other theoretica l data. The 2p(3)(S-4) --> 1s2p(2)(P-4) transition wavelength for the isoelectronic series is also computed. The overall good agreement of o ur results with the literature data indicates the reliability of the p resent density functional methodology for excited states of many-elect ron systems. (C) 1997 John Wiley & Sons, Inc.