Formation of Excited Molecules and Atoms by Controlled Electron Impact on Hydrogen Chloride and Chlorinated Methanes

Abstract

Abstract The dissociation, ionization, and excitation of hydrogen chloride and chlorinated methanes under controlled electron-impact excitation were studied at low pressures. The photoemissions (200–600 nm) were observed and assigned to HCl+, CH, CH+, CCl, H, and Cl+. Such species as H and HCl+ from HCl, and H and CH from CH2Cl2 were concluded to be produced by some one-electron processes. The photoemission of the HCl+ produced from CH2Cl2 increases quadratically with the electron-beam current; in this case HCl+ is mainly produced by the molecular elimination of HCl and the successive ionization excitation by the second electron. The threshold energies of the photoemissions were found to be 16.8 eV for HCl+* from HCl, 19.8 eV for H* from HCl, and 17.6 eV for CH*(A) from CHCl3. The processes of the excitation of these species near the threshold were discussed.