Electron emission from methane, ammonia, monomethylamine, and dimethylamine by 0.25 to 2.0 MeV protons

Absolute cross sections, differential in electron energy and emission angle, have been measured for ejection of electrons from methane, ammonia, monomethylamine, and dimethylamine by 0.25 to 2.0 MeV protons. Electron energy distributions are presented for 12 emission angles between 15° and 125°. The results indicate that emission cross sections for electrons ejected with energy greater than about 1 eV show no effects related to molecular structure for this group of molecules, within experimental uncertainty. The double‐differential cross sections are found to be scalable in terms of the number of weakly bound electrons per molecule. Total ionozation cross sections are determined by integration of the double‐differential cross sections with respect to energy and angle. The results are compared with the results for other low‐Z polyatomic molecules, and also in the case of methane, with results from electron impact ionization.