Electric dipole transitions in the carbon isoelectronic sequence calculated with symmetric states obtained from superposition of configurations

Abstract

Sinanoğlu's nonclosed shell many electron theory (NCMET) is used to determine and analyze symmetry-adapted correlated wavefunctions for states of the F(IV) ion belonging to the 1s 22s 22p2 and 1s 22s 2p3 configurations. We argue that these wavefunctions contain those specific correlation effects important in calculating accurate oscillator strengths for allowed transitions between states of these two configurations. The types of correlations included, the reasons for their importance, the methods of approximating them, and the necessity and techniques for introducing symmetry into these calculations are discussed. Comparison of results using Hartree-Fock as opposed to correlated wavefunctions clearly shows the necessity of including correlation effects in calculating the electric-dipole oscillator strengths in F(IV). The conclusion follows for both the dipole-velocity and the dipole-length formulations. These new results for the six electric-dipole transitions in F(IV) are combined with previously published results for the same transitions in the isoelectronic species C(I), N(II), O(III) in order to extrapolate the Z dependence of these transitions and thereby make reasonable predictions of the oscillator strengths for the heavier ions. We conclude with a formalism, based on plausible but as yet unproven speculations, which shows in a transparent way what correlation effects are of significance in the general problem of computing oscillator strengths.