Angular distribution of electrons elastically scattered from water vapor

The angular distributions of electrons elastically scattered from ${\mathrm{H}}_2$O have been measured by electron impact using a modulated crossed-beam method. The energy and angular range measured were from 30 to 200 eV and 12° to 156°, respectively. The present results show a high backward scattering for low incident energies, but this falls off for high incident energies. The present results are in qualitative agreement with the measurements of Danjo and Nishimura [J. Phys. Soc. Jpn. 54, 1224 (1985)] and in quantitative agreement with the measurements of Katase et al. [J. Phys. B 19, 2715 (1986)]. Agreement between the present results and the calculation of Jain, Tripathi, and Jain [Phys. Rev. A 37, 2893 (1988)] is good except at 200-eV impact.