Universal convergent scaling laws of high-nintercombination transitions in helium

Abstract

A general expression for intercombination spontaneous transition probabilities A int in neutral helium is proposed. Consideration of the wavefunction mixing for high n-states showed that interference effects between the upper and lower states lead to a drastic decrease of the transition probabilities for high angular momentum states. This allowed us to develop convergent expressions for A int up to very high principal quantum numbers n. Spin-dependent atomic population kinetics demonstrate the particular influence of interference effects for the singlet/triplet population of high n-states and cascades driven by intercombination transitions.

Fluctuating Helium Emission in Optically Thick Divertor Plasmas

“…Quantum mechanical calculations of cross sections and rate coefficients for collisional rate coefficients, transition probabilities and dielectronic recombination have been performed. More details are described in [24][25][26].…”