Feshbach-Fano Approach for Calculation of Auger Decay Rates Using Equation-of-Motion Coupled-Cluster Wave Functions: Numerical Examples and Benchmarks

This manuscript is concerned with numerical illustration of the theoretical framework for computing Auger decay rates based on the Feshbach-Fano approach and the equation-of-motion coupled-cluster ansatz, augmented with core-valence separation scheme. We consider two analytical approximations to the continuum orbital describing the Auger electron: a plane wave and a Coulomb wave with an effective charge. Theoretical Auger electron spectra are presented for benchmark systems (Ne, H₂O, CH₄ and CO₂) and compared with available experimental spectra. Results of the presented benchmark tests show that the proposed computational scheme provides reliable ab initio preditions of the Auger spectra. The reliability, cost-efficiency, and robust computational setup of this methodology offer advantages in applications to a large variety of systems.