A reinvestigation of the vibrational structure and the orbital assignments in the photoelectron bands of cyclopropane

Abstract

The valence shell photoelectron spectrum of cyclopropane has been studied using synchrotron and HeI radiation. The photoelectron asymmetry parameters and branching ratios have been determined using monochromated synchrotron radiation in the photon energy range 15–120 eV. The spectral behaviour of the asymmetry parameters associated with the outer valence orbitals has been used to propose an assignment for the valence shell electronic configuration. The experimental features observed in the inner valence energy region of the photoelectron spectrum have been compared with theoretical predictions. The high resolution HeI excited spectrum has allowed vibrational structure to be observed in the outer valence photoelectron bands, and in two of the bands these features can be assigned to progressions involving the ν 2 (a 1′) and ν 11 (e′) modes. The X̃ 2E′ photoelectron band, which exhibits a doublet structure due to Jahn–Teller interaction, displays an extended vibrational progression in the doubly degenerate ν 11 (e′) mode.