University of Oulu

D.M.P. Holland, S. Nandi, C. Nicolas, J.D. Bozek, M. Patanen, I. Powis, An experimental and theoretical study of the valence shell photoelectron spectrum of oxalyl chloride, Chemical Physics, Volume 542, 2021, 111050, ISSN 0301-0104,

An experimental and theoretical study of the valence shell photoelectron spectrum of oxalyl chloride

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Author: Holland, D.M.P.1; Nandi, S.2,3; Nicolas, C.2;
Organizations: 1Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD, UK
2Synchrotron SOLEIL, L’Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
3Université de Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France
4Nano and Molecular Systems Research Unit, Faculty of Science, University of Oulu, P. O. Box 3000, 90014 Oulu, Finland
5School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
Format: article
Version: accepted version
Access: open
Online Access: PDF Full Text (PDF, 1.1 MB)
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Language: English
Published: Elsevier, 2021
Publish Date: 2022-11-18


Polarization dependent photoelectron spectra encompassing the outer valence orbitals of oxalyl chloride have been recorded in the photon energy range 19–91 eV. These have allowed photoelectron anisotropy parameters and branching ratios to be determined. Photoionization partial cross sections and photoelectron anisotropy parameters have been calculated with the Continuum Multiple Scattering — Xα approach. Four of the outer valence orbitals are predicted to possess a significant Cl 3p lone-pair character and have closely grouped binding energies. The photoionization dynamics of these four orbitals are predicted to be strongly affected by the Cooper minimum associated with the Cl 3p orbital in the isolated atom at photon energies around 40 eV. A comparison between the theoretical and measured photoelectron anisotropy parameters has enabled the molecular orbital sequence to be clarified. A doublet has been observed in the region of the photoelectron spectrum where a band due to the 5bu orbital might be anticipated. Our calculations indicate that the 6bu and 5bu orbitals are coupled. This coupling may account for the apparent lack of a pronounced Cooper minimum in the β-parameter associated with the nominal 6bu ionization and for the unexpected appearance of the adjacent photoelectron band, nominally associated with the 5bu orbital. The vertical ionization energy of the outermost 7ag orbital was experimentally determined to be 11.266 ± 0.005 eV.

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Series: Chemical physics
ISSN: 0301-0104
ISSN-E: 1873-4421
ISSN-L: 0301-0104
Volume: 542
Article number: 111050
DOI: 10.1016/j.chemphys.2020.111050
Type of Publication: A1 Journal article – refereed
Field of Science: 114 Physical sciences
116 Chemical sciences
Funding: DMPH is grateful to the Science and Technology Facilities Council (United Kingdom) for financial support. We are grateful for access to the University of Nottingham High Performance Computing Facility. We acknowledge the provision of beamtime by Synchrotron Soleil (beamtime Proposal No. 20150589), and we thank the technical staff at Soleil for their support and for the smooth operation of the facility.
Dataset Reference: Raw data were generated at the Synchrotron Soleil large scale facility. Derived data supporting the findings of this study are available from the corresponding author upon reasonable request.
Copyright information: © 2020 Elsevier B.V. This manuscript version is made available under the CC-BY-NC-ND 4.0 license