The Auger spectrum of benzene

02 January 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


We present an ab initio computational study of the Auger electron spectrum of benzene. Auger electron spectroscopy exploits the Auger-Meitner effect and, although it is established as an analytic technique, the theoretical modeling of molecular Auger spectra from  first principles remain challenging. Here, we use coupled-cluster and equation-of-motion coupled-cluster theory combined with two approaches to describe the decaying nature of core-ionized states: (i) Feshbach-Fano resonance theory and (ii) the method of complex basis functions. The spectra computed with these two approaches are in excellent agreement with each other and also agree well with experimental Auger spectra of benzene. The Auger spectrum of benzene features two well-resolved peaks at Auger electron energies above 260 eV that correspond to  final states with two electrons removed from the 1e1g and 3e2g highest occupied molecular orbitals. At lower Auger electron energies, the spectrum is less well resolved and the peaks comprise multiple  final states of the benzene dication. In line with theoretical considerations, singlet decay channels contribute more to the total Auger intensity than the corresponding triplet decay channels.


X-ray spectroscopy
Auger decay
Feshbach-Fano approach
Complex basis functions
Equation-of-motion coupled-cluster

Supplementary materials

Comparison of experimental spectra, and additional results
Comparison of three experimental spectra corresponding to Auger decay in benzene. Additional results comprising of partial decay widths and spectra from individual ionization using Feshbach-Fano, and the method of complex basis functions. Cartesian coordinates, as well as sample jobs used in the calculations.


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