Wannier Analytic Continuation to Helium Negative Ion Resonances

The uniform, semiclassical wave function [D.S.F. Crothers, J.Phy.B 19, 463 (1986)] has been analytically continued to below the energy threshold in order to calculate the complex eigenenergies for doubly excited states of helium using a complex Bohr-Sommerfeld quantization rule with at least one complex transition point. The real parts of the eigenvalues are in good agreement with the experimental results of Buckman etal. [S.J.Buckman etal., J.Phys.B 16, 4039 (1983); S.J. Buckman and D.S. Newman, J.Phys.B 20, L711 (1987)] for the resonance positions while the imaginary parts give the explicit widths of the resonances from which intensities have been estimated. copyright 1997 The American Physical Society