Photoionization mass spectrometry of gaseous ethene and fluoroethenes in the energy range 280–300 eV

Abstract

The photoionization mass spectra of the parent cations of ethene, fluoroethene, 1,1′-difluoroethene, cis-difluoroethene, trifluoroethene and tetrafluoroethene have been measured in the energy range 280–300 eV. Below, the C1s ionization limits strong resonances are observed, which are assigned to C(1s) → π * and C(1s) → R transitions. The term values of the core excited valence states are strongly increased compared to those of π → π * transitions. The 1s core hole causes negligible shifts in the Rydberg states. Ab initio MRD CI calculations are used to interpret the experimental results.