Configuration-interaction studies of transition energies and oscillator strengths for the lowest quartet states of neutral lithium

Abstract

Configuration-interaction calculations for the lowest ${}_{}{}^4{}_{}{}^{}S$, ${}_{}{}^4{}_{}{}^{}P_{}^o{}_{}{}^{}$, ${}_{}{}^4{}_{}{}^{}P$, ${}_{}{}^4{}_{}{}^{}D_{}^o{}_{}{}^{}$, ${}_{}{}^4{}_{}{}^{}D$, ${}_{}{}^4{}_{}{}^{}F_{}^o{}_{}{}^{}$, and ${}_{}{}^4{}_{}{}^{}F$ states of neutral lithium have been carried out with a basis of $10s8p8d6f3g2h1i$ Slater-type orbitals. The nonrelativistic-energy upper bounds converge to within 4-45 ${\mathrm{cm}}^{-1\mathrm{}}$ of the expected nonrelativistic energies. An explanation is given for the fact that transitions from ${}_{}{}^4{}_{}{}^{}F$ states have not been observed in beam-foil experiments. Some aspects involved in the assessment of the reliability of calculated oscillator strengths are discussed, and the calculated mean lifetimes for electric dipole decay are compared with experiment.