Spin-forbidden radiative decay rates from the3 3P1,2and3 1P1states of helium

Abstract

We have calculated atomic helium spontaneous decay rates and absorption oscillator strengths for the spin-forbidden transitions from $3 {}^{3}{P}_{1,2}$ and $3 {}^{1}{P}_{1}$ to all lower ${}^{1}{S}_{0}$ and ${}^{3}{S}_{1}$ states. In particular we found ${A}_{10}=44.33(4) {\mathrm{s}}^{\ensuremath{-}1}$ for the $E$1 transition $3 {}^{3}{P}_{1}$--$1 {}^{1}{S}_{0}$ and 0.1147(1) ${\mathrm{s}}^{\ensuremath{-}1}$ for the $M$2 transition $3 {}^{3}{P}_{2}$--$1 {}^{1}{S}_{0}$.