Penning ionization of [2,2]-paracyclophane by collision with metastable He *( [formula omitted]) atoms

Abstract

Penning ionization of [2,2]-paracyclophane (PC) with metastable He *( 2 3 S ) atoms has been studied by means of simultaneous detection of collision energy and electron energy. Negative collision energy dependences of partial Penning ionization cross-sections have been observed in the range of 115–283 meV. This indicates the presence of an attractive potential well around PC. Assignments of Penning ionization electron and HeI ultraviolet photoelectron spectra have been made by outer valence Green's function calculations. Molecular-orbital and model-potential calculations have also been performed, and the characteristic features of electron density and interaction potential are discussed in comparison with the case of benzene.