The electron scattering cross-section of atomic oxygen and water molecules.

Abstract

We have measured absolute differential cross sections for the electron impact excitation of the $\sp1$S state of atomic oxygen, utilizing a modulated crossed-beam method. The incident energies of 10, 15, 20 and 30eV were used and the angular range was from 30 to 150$\sp\circ$ in 15$\sp\circ$ intervals. Also the elastic (vibrationally) cross sections and the vibrational excitation cross sections of water molecules (ground state) have been measured by electron impact. The energy and angular range covered for the measurements were from 2.2 to 20eV and from 15 to 150$\sp\circ$, respectively. The integrated cross sections and momentum transfer cross sections of the elastic scattering were obtained by integrating over scattering angles. The vibrational excitation cross sections measured were a bending mode (010) and two stretching modes (100), (001). The integrated cross sections of the vibrational excitations were obtained by integrating over scattering angles.