METASTABLE SPECIES PRODUCED BY ELECTRON EXCITATION OF N2 H2 N2O AND CO2

A molecular beam is crossed by an electron beam to produce metastable molecules and fragments which are detected by electron ejection from a Cs 3Sb cathode in a chamber operating at ultrahigh vacuum. Excitation functions for the production of H2(c 3IIu) molecules and of photons from H2 are reported. The time-of-flight distribution of the slow group of H (2S) atoms from H2 has been measured and this differs from a previously reported distribution. Threshold-energy and kinetic-energy measurements have been made on the electronically excited fragments known to be produced in the dissociative excitation of CO2 and N2O. It is postulated that in CO2 the initial products are CO (a 3II) and O-. A new excitation curve for the E3Σg+ state of N2 was determined.