Highest Occupied Molecular Orbital of Cyclopentanone by Binary(e, 2e) Spectroscopy

Abstract

We report the first measurements of the momentum profiles of highestoccupied molecular orbital (HOMO) and the complete valence shellbinding energy spectra of cyclopentanone with impact energies of 600and 1200 eV by a binary (e, 2e) spectrometer. The experimental momentumprofiles of the HOMO orbital are compared with the theoretical momentumdistribution calculated using the Hartree–Fock and density functionaltheory methods with various basis sets. However, none of thesecalculations gives a completely satisfactory description of themomentum distributions of the HOMO 7b2. The inadequacy ofthe calculations could result in the intensity difference of the secondmaximum at p~1.2 a.u. between the experiment and thetheory. The discrepancy between experimental and theoretical data inthe low-momentum region is explained with the distorted wave effect.