The Resonant and Normal Auger Spectra of Ozone

In this work, we outline a general method for calculating Auger spectra in molecules, which accounts for the underlying symmetry of the system. This theory starts from Fano’s formulation of the interaction between discrete and continuum states, and it generalizes this formalism to deal with the simultaneous presence of several intermediate quasi-bound states and several non-interacting decay channels. Our theoretical description is specifically tailored to resonant autoionization and Auger processes, and it explicitly includes the incoming wave boundary conditions for the continuum states and an accurate treatment of the Coulomb repulsion. This approach is implemented and applied to the calculation of the K−LL Auger and autoionization spectra of ozone, which is a C2v symmetric molecule, whose importance in our atmosphere to filter out radiation has been widely confirmed. We also show the effect that the molecular point group and, in particular, the localization of the core-hole in the oxygen atoms related by symmetry operations, has on the electronic structure of the Auger states and on the spectral lineshape by comparing our results with the experimental data.

The Resonant and Normal Auger Spectra of Ozone

In this work we outline a general method for calculating Auger spectra in molecules, which accounts for the underlying symmetry of the system. This theory starts from Fano’s formulation of the interaction between discrete and continuum states and generalizes this formalism to deal with the simultaneous presence of several intermediate quasi-bound states and several non-interacting decay channels. Our theoretical description is specifically tailored to resonant autoionization and Auger processes, and includes explicitly the incoming wave boundary conditions for the continuum states and an accurate treatment of the Coulomb repulsion. This approach is implemented and applied to the calculation of the K−LL Auger and autoionization spectra of ozone, which is a C2v symmetric molecule, whose importance in our atmosphere to filter out radiation has been widely confirmed. We also show the effect that the molecular point group, and in particular the localization of the core-hole in the oxygen atoms related by symmetry operations, has on the electronic structure of the Auger states and on the spectral lineshape by comparing our results with experimental data.

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

<p>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 <i>ab initio</i> 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. </p>

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

<p>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 <i>ab initio</i> 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. </p>