Fine structure of the 2 3P state of the helium atom

Abstract

The fine structure of the 2 3P state of the He atom depends on the spin-spin and spin-orbit interactions. It follows from the experimental splittings that the matrix element of the spin-spin interaction is 0.052767 cm−1 and the matrix element of the spin-orbit interaction is −0.196519 cm−1. We calculated the spin-spin interaction from a simple correlated wavefunction that may be used also for more complex systems. Our result is 0.053614 cm−1; this agrees with the experimental value to within 1.8%. We found that our correlation wavefunction is not particularly suitable for calculating the spin-orbit coupling.