Journal of Physics B: Atomic, Molecular and Optical Physics
High-precision variational eigenvalues are obtained for the 10D, 10F, 10G and 10H states of helium by the application of multiple basis set methods. The accuracy is sufficient to provide the first definitive test of asymptotic expansion methods extensively developed by Drachmann (1982-8) for Rydberg states of high angular momentum. The results are also compared with recent high-precision measurements for the 10G-10H and 10F-10G transition frequencies, and interpreted in terms of predicted long-range retardation corrections. Bethe logarithms are calculated and Lamb shift corrections included. Small residual discrepancies persist which could be explained by uncalculated radiative shifts.
Drake, Gordon W. F.. (1989). Eigenvalues and retardation effects in the n=10 states of helium. Journal of Physics B: Atomic, Molecular and Optical Physics, 22 (23), L651-L657.