DOUBLY-EXCITED STATES OF HIGHLY STRIPPED IONS - A TIME-DEPENDENT PERTURBATION APPROACH

Doubly excited singlet states have been calculated for the astrophysic ally important highly stripped He like ions Al11+, Si12+, P13+, S14+ a nd Cl15+ for the transitions 2s(2): S-1(e), 2p(2): D-1(e), 2snp: P-1(0 ), 2snd: D-1(e) and 2pnd: F-1(0) for n less than or equal to 5. The tr ansition energies are obtained from the position of resonances in the oscillations of the two electron charge cloud under an external harmon ic perturbation. Linearised version of a suitably constructed variatio nal functional is used for obtaining the response properties of the sy stem. Most of the results are new. Agreement with the only few existin g experimental data along this line is very reasonable. Analytic repre sentations of the doubly excited states are obtained and the Coulomb r epulsion integral in these states are estimated for checking the consi stency of the wavefunctions. The doubly excited state wavefunctions so obtained may be used for evaluating other physical properties connect ed with transitions.