Energy Levels and Lifetimes of 1s2 and 1snl (n=2-5) for Neutral Helium

Abstract

In this paper, we present calculations for some of the lowest energy levels and lifetimes for neutral helium. The FAC (Flexible-Atomic-Code) is a reliable code for calculating 49 energy levels and their lifetimes. The calculation is performed up to n=5 including a series of configuration of 1s2 and 1snl. Comparison has been made with similar data published in the NIST database. A good agreement of less than1% was found for most levels expect the 1s2p 3P2 level. This proves the reliability of our results. New values for lifetimes are presented for the first time.