Unusual features in electron attachment to chlorodifluoroacetic acid (CClF 2COOH): Strong dissociative electron attachment near 0 eV and associative attachment at 0.75 eV

Abstract

Electron attachment to gas phase CClF 2COOH (M) under collision free conditions exhibits very unusual features as the non-decomposed parent anion M − (associative attachment) is observed on the mass spectrometric time scale at a resonance located at 0.75 eV while strong dissociative electron attachment (DEA) reactions already occur within a resonant feature close to 0 eV. Long lived parent anions M − are usually only formed (if at all) at energies close to 0 eV and when no DEA channels are energetically accessible. The two by far dominant DEA reactions are due to the cleavage of the C–Cl bond with the excess charge localised on either of the fragments to form the closed shell anions CF 2COOH − or Cl −. Electron attachment near 0 eV also leads to more complex DEA reactions like the loss of HF or CF 2, etc., which are associated with substantial geometrical and electronic rearrangement. The thermal attachment rate constant is derived by means of an electron swarm experiment as k = 1.5 × 10 −10 cm 3 molec. −1 s −1.