Vibrationally elastic scattering cross section of water vapor by electron impact

Absolute differential cross sections of electrons vibrationally elastically scattered from water vapor have been measured at room temperature by electron impact. A modulated crossed-beam method was used. The energy and angular range covered were from 2.2 to 20 eV and from 15^∘{} to 150^∘{}, respectively. Strong backward scattering has been observed as predicted by theory. The measured integrated and momentum-transfer cross sections are generally larger than others in the literature by 50%.