Energy levels for the stable isotopes of atomic helium(4He I and 3He I)

Abstract

We calculate very accurate ab initio ionization energies for both 4He I and 3He I as well as the isotope shifts for n = 1 to 10, L = 0 to 7 and combined these with precise laboratory data to produce a new table of levels for 4He I and the first table for 3He I. We adopted an experimental ionization potential of 5945 204 290 ± 33 MHz for 4He I and derived 5944 890 770 ± 33 MHz for 3He I. Additional calculations of the magnetic perturbations of 3He I provide the hyperfine levels, which compare favourably with the available measurements.PACS Nos.: 31.30.Gs, 31.30.Jv