Dissociative electron attachment to gas phase alanine

Using a high resolution electron energy monochromator the dissociative electron attachment (DEA) to the gas phase l-alanine is studied by means of the mass spectrometric detection of the product anions. Alanine and the previously studied amino acid glycine exhibit several common features due to the possibility of electron attachment to the unoccupied π* orbital of the -COOH group. The largest DEA cross-section of about 1.5 × 10−20 m2 is observed for the production of the (A − H)− ion at the electron energy of 1.27 eV. This ion is the major reaction product at electron energies below 5 eV. At higher incident electron energies several smaller fragment anions are formed via core excited resonances at about 5.5 and 9.0 eV.