Abstract

The photoionization cross sections of helium have been measured from threshold down to 260 Å. At the spectral head the cross section is found to be 7.3×10⁻¹⁸ cm². The experimental results are compared to available theoretical data. The oscillator strength for transitions into the ionization continuum have been estimated from threshold to 0.01 Å using the present and previously published data. A continuum f value of 1.54 is obtained. Applying the Thornas–Kuhn sum rule one therefore obtains the total oscillator strength for all discrete transitions as f = 0.46.

© 1964 Optical Society of America

Photoionization Cross Sections of Neon from Threshold to 200 Å

James A. R. Samson
J. Opt. Soc. Am. 55(8) 935-937 (1965)

Photoionization and Absorption Cross Sections of H₂ and D₂ in the Vacuum Ultraviolet Region

G. R. Cook and P. H. Metzger
J. Opt. Soc. Am. 54(8) 968-972 (1964)

Flux Distribution of the Hopfield Helium Continuum from the Photoionization of Ar, Kr, and Xe

P. H. Metzger and G. R. Cook
J. Opt. Soc. Am. 55(5) 516-520 (1965)

Absorption Cross Sections of Argon and Methane between 600 and 170 Å

Om Prakash Rustgi
J. Opt. Soc. Am. 54(4) 464-466 (1964)

Absorption Cross Sections and f Values of Krypton and Xenon in their Ionization Continuum

Om P. Rustgi, E. I. Fisher, and C. H. Fuller
J. Opt. Soc. Am. 54(6) 745-746 (1964)