Free electron attachment to the chloromethane CHCl3

Dissociative electron attachment (DEA) to chloroform (CHCl3) is studied in the electron energy range from about 0 up to 25 eV. The measurements are carried out with a two sector field mass spectrometer providing very high mass resolution and sensitivity. The ion yields of anions formed close to 0 eV are also measured utilizing a hemispherical electron monochromator providing an electron energy resolution better than 70 meV. In agreement with previous studies we observe Cl− as the most abundant anion formed in DEA to CHCl3 with a distinct peak at about 0 eV and the main resonance at about 300 meV. Moreover, due to the high sensitivity of the two sector field instrument we are also able to determine the ion yield of nine other product anions (H−, C−, CH−, CCl−, CHCl−, Cl2−, HCl2−, CCl2− and CHCl2−) formed via DEA to chloroform. The present results are compared with previous data of DEA to chloroform in the gas phase and in the condensed phase.