Studies of H+, H+2, and H+3 dissociative ionization fragments from methane, ethane, methanol, ethanol, and some deuterated methanols using electron-impact excitation and a time-of-flight method incorporating mass analysis

Abstract

Kinetic energy distributions and relative intensities of energetic (≳1eV) H⁺,H⁺₂, and H⁺₃ dissociative–ionization fragments from methane, ethane, ethanol, and methanol have been measured using pulsed electron‐impact excitation and a time‐of‐fight method incorporating a new mass analysis technique. The various deuterated analogs of H⁺, H⁺₂, and H⁺₃ fragments were also observed from CH₃OD, CD₃OH, and CD₃OD. Results for these deuterated fragments show that energetic H⁺₂ and H⁺₃ fragments originate primarily from the −CH₃ group, rather than from H atom extraction from both the−CH₃ and −OH groups. Comparisons among the kinetic energy distributions of these light fragments from CH₃OH, CD₃OD, and CD₃OH reveal no major isotope effects for fragment energies exceeding 2 eV.