Fan, ZhuangSadeghpour, H. R.Dalgarno, A.2019-09-271994Fan, Zhuang, H. R. Sadeghpour, and A. Dalgarno. 1994. “Photoexcitation and -Ionization in Helium: Zero-Kinetic-Energy Spectroscopy.” Physical Review A 50 (4): 3174–76. https://doi.org/10.1103/physreva.50.3174.1050-29471094-1622http://nrs.harvard.edu/urn-3:HUL.InstRepos:41417403The cross sections for double and single photoexcitation and -ionization of helium are calculated in the acceleration gauge assuming a totally asymmetric energy and angular momentum partitioning between two electrons. The electron-electron correlation is taken, into account in the ground-state wave function. By extrapolating single-ionization differential oscillator strengths to n --> infinity, where n is the excited He+ principal quantum number, an estimate of the double-ionization cross sections is obtained. Comparison with other calculations is made.en-USJournal Article2019-09-2710.1103/PhysRevA.50.3174