Ab initio calculations of molecular double Auger decay rates

TL;DR

This paper introduces a new computational method, Fano-ADC(2,2), for accurately calculating molecular double Auger decay rates and spectra, showing excellent agreement with experimental data.

Contribution

The paper presents the application of the Fano-ADC(2,2) method to compute both total and partial Auger decay widths, including double decay modes, with high accuracy across atoms, molecules, and clusters.

Findings

Decay widths and spectra agree well with experiments

Double Auger decay branching ratios have about 30% error

Method effectively describes complex multi-electron decay processes

Abstract

We report on the application of the recently developed Fano-ADC(2,2) method to compute total and partial Auger decay widths of molecular core-hole states, including explicit evaluation of double Auger decay branching ratios. The method utilizes the fast-convergent intermediate state representation to construct many-electron wave functions and is readily applicable to atoms, molecules and clusters. The ADC(2,2) scheme describes the initial and final states of the normal Auger decay consistently up to the second order of perturbation theory. In addition, excitations with two electrons in the continuum provide access to three-electron decay modes. The method yields decay widths and the Auger electron spectra in excellent agreement with the experiment, demonstrating the high accuracy of partial widths. The average relative error of double Auger decay branching ratios compared to available experimental data is about 30\%, which should be evaluated as an excellent result considering the universality of the method, the complexity of the double decay process and the neglection of nuclear motion in the present study.