Electron ionization and photoionization of cyclopropylamine

Abstract

We present an experimental and theoretical study of electron ionization (EI) of Cyclopropylamine (CPA) molecule, using crossed electron – molecular beam technique with mass spectrometric detection of the ions. We have obtained energy resolved mass spectra, and electron energy dependent ion efficiency curves for ions of particular mass charge ratios (m/z). Except the ionization energy of the CPA molecule (8.46 ± 0.20 eV) we have evaluated the appearance energies of most of the ions in the mass spectrum formed via dissociative ionization (DI) processes. In addition we have carried out He∗ photoelectron spectrometry (PES) and determined the vertical ionization energy (VIE) of 9.47 ± 0.1 eV and detected the excited states of CPA. PES study was supported by outer valence green function (OVGF) calculation of the vertical ionization energy (9.55 eV). We have carried out quantum-chemical calculations of the neutral molecule, of the molecular ions, the neutral and ionic fragments and the reaction enthalpies for the DI processes were calculated. The theoretical DI values were applied for identification of the DI reactions and fragment ions in experiment.