COMPARISON OF CALCULATED OSCILLATOR STRENGTHS FOR SI 3

Oscillator strengths have been calculated for many of the major transitions in Si III using both dipole length and dipole velocity matrix elements. Three approximations to the many-electron correlation problem are explored and compared: (1) the use of configuration interaction employing a semiempirical frozen core potential; (2) the use of configuration interaction employing a modified Hartree-Fock-Slater basis set; and (3) the use of the Coulomb approximation whereby a wavefunction is constructed with the correct asymptotic behavior. None of these methods as far as they have been carried out here is found to be fully satisfactory. Emphasis is placed upon the difficulty of calculating transition probabilities between high-lying energy levels which are strongly perturbed. © 1969.