MCHF OSCILLATOR STRENGTH AND LIFETIME CALCULATIONS IN NEUTRAL CALCIUM

We report extensive multiconfiguration Hartree-Fock (MCHF) calculations, taking into account valence correlation and core-relaxation effects, of energy levels, eigenvector compositions, electric dipole and quadrople oscillator strengths involving the n1S (n = 1 - 4), n1P(o) (n = 1, 2), n1D (n = 1 - 3) and n1F(o) (n = 1, 2) states in Ca I. On the whole, the agreement between theory and observation has been improved by our set of MCHF results. The theoretical transition probabilities allow the evaluation of the lifetimes for the levels 4s4p, 4s5p 1P(o); 4s4d, 4p2 1D and 3d4p, 4s4f 1F-degrees which are compared with the most recent measurements. The differences between MCHF calculations for series perturbed by doubly-excited states in Ca and Sr are discussed. It is concluded that core-polarization effects are of about the same importance in the two atoms but that the effects on the 3d (Ca) and 4d (SR) orbitals are such that the total core-polarization effects for series and perturbers are of the same magnitude in Sr while large differences exist in Ca.