A scaled CIS(D) based method for the calculation of valence and core electron ionization energies

Hanson-Heine, Magnus W. D.; George, Michael W.; Besley, Nicholas A.

Abstract

The calculation of electron ionisation energies is a key component for the simulation of photoelectron spectroscopy. CIS(D) is a perturbative doubles correction for the single excitation configuration interaction (CIS) method which provides a new approach for computing excitation energies. It is shown that by introducing a virtual orbital subspace that consistsofasingle’ghost’orbital,valenceelectronionisationenergiescanbecomputedusingascaledCIS(D)approach with an accuracy comparable with considerably more computationally intensive methods, such as ionisation-potential equationofmotioncoupledclustertheory(EOM-IP-CCSD),andsimulatedspectrashowasignificantimprovementrelative to spectra based upon Koopmans’ theorem. When the model is applied to the ionisation energies for core orbitals thereis anincrease intheerror, particularlyfor theheavier nucleiconsidered (siliconto chlorine), althoughthe relative energy of the ionisation energies are predicted accurately. In addition to its inherent computational efficiency relative to other wavefunction based approaches, a significant advantage of this approach is that the ionisation energies for all electrons can be obtained in a single calculation, in contrast to∆self-consistent field based methods.

Citation

Hanson-Heine, M. W. D., George, M. W., & Besley, N. A. (2019). A scaled CIS(D) based method for the calculation of valence and core electron ionization energies. Journal of Chemical Physics, 151(3), Article 034104. https://doi.org/10.1063/1.5100098

• Journal Article Type: Article
• Acceptance Date: Jun 19, 2019
• Online Publication Date: Jul 15, 2019
• Publication Date: Jul 21, 2019
• Deposit Date: Jul 16, 2019
• Publicly Available Date: Jul 17, 2019
• Journal: The Journal of Chemical Physics
• Print ISSN: 0021-9606
• Electronic ISSN: 1089-7690
• Publisher: American Institute of Physics
• Peer Reviewed: Peer Reviewed
• Volume: 151
• Issue: 3
• Article Number: 034104
• DOI: https://doi.org/10.1063/1.5100098
• Keywords: Physical and Theoretical Chemistry; General Physics and Astronomy
• Public URL: https://nottingham-repository.worktribe.com/output/2311935
• Publisher URL: https://aip.scitation.org/doi/10.1063/1.5100098
• Additional Information: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in J. Chem. Phys. 151, 034104 (2019) and may be found at (https://doi.org/10.1063/1.5100098
• Contract Date: Jul 16, 2019