Low-Energy Electron Impact Ionization of Molecular Hydrogen

Relative doubly-differential cross sections for the electron impact ionization of molecular hydrogen have been measured at incident energies of 25~eV and 40~eV and scattering angles of $20^{\circ}$ to $130^{\circ}$. The calibration of the electron analyzer during these measurements employed the recent doubly-differential cross section measurements of atomic hydrogen.\footnote{J.G.Childers, K.\ E.\ James, Jr., Igor Bray, M.\ Baertschy, and M.A.Khakoo, {\em Phys.\ Rev.\ A} {\bf 69}, 022709 (2004).} These measurements represent a new calibration standard useful in the determination of the transmission function of electron analyzers. This work is funded by the National Science Foundation under grant \# NSF-RUI-PHY-9731890.