Electron-ion coincidence measurements of CH₄

Abstract

Measurements are reported of 10 keV electron scattering in CH 4 at low momentum transfers, in coincidence with the various ionic products. Ion mass separation was performed in a time-of-flight system with total transmission for fragments with dissociation energies up to 20 eV. Results have been obtained on the oscillator strengths for the formation of all ionic products for energy losses from the IP up to 80 eV. The present results confirm earlier electron-electron coincidence measurements of the photoionization efficiency (see ibid., vol.8, no.18, p.3007 (1975)) and extend them to higher energy. The oscillator strengths of the (1t 2 ) -1 , (2a 1 ) -1 and higher initial states of CH 4 + could be extracted separately from the data.