Measurement of Total Inelastic Cross Sections for Electron Impact in N2 and CO2

Abstract

We use the trapped-electron method to study the total inelastic cross sections for electron impact in N2 and CO2 in the energy region of the low-lying compound states. These compound states are centered energetically at about 2.5 and 3.8 eV above the ground state of N2 and CO2, respectively. The measurement gives the total cross section for the excitation of vibrational states which lie above about 1 eV. A reasonable extrapolation gives an indication of the total cross section for excitation of vibrational states at 2.5 eV in N2 and 3.8 eV in CO2. For N2, the value of 6.0×10−16 cm2 is in excellent agreement with the analysis of the swarm data by Engelhardt, Phelps, and Risk. For CO2 the total inelastic cross section in the region of 3.8 eV is 8.3×10−16 cm2, almost an order of magnitude larger than the previously published value.