Triplet Intervals of Helium

Abstract

The triplet intervals of the deepest $P$-state of helium are calculated by making use of the wave function recently determined by the present authors. The polarization of the $s$-orbital, the admixture of the singlet, and the quantum-electrodynamic fourth-order correction are all taken into account. The theoretical values of the intervals are ${}_{}{}^3{}_{}{}^{}P_0^{}{}_{}{}^{}-{}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}=997.457\mathrm{}11\times {10}^{-3\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$ and ${}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}-{}_{}{}^3{}_{}{}^{}P_2^{}{}_{}{}^{}=75.974\mathrm{}45\times {10}^{-3\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$.