Measurement of the photoelectric cross section ofH2at 5.4 and 8.4 keV

Abstract
The photoelectric cross section of molecular hydrogen has been measured by counting photoelectrons released by monochromatized x rays traversing highly purified H2 gas. Results are 54.0 ± 2.9 mb/atom at 5.41 keV and 12.0 ± 0.6 mb/atom at 8.39-keV incident-photon energy. The effect of molecular bonding is pronounced: The measured cross section, per atom, exceeds the theoretical atomic cross section by (44 ± 8)% at 5.41 keV and by (45 ± 7)% at 8.39 keV. A comparable effect has been predicted by Kaplan and Markin.