On the computations of interatomic Coulombic decay widths with R-matrix method.

Area of Science:

• Atomic and Molecular Physics
• Quantum Chemistry
• Computational Physics

Background:

• Interatomic Coulombic Decay (ICD) is a resonant process where an excited atom ionizes a neighbor.
• ICD processes are characterized by their energy width, crucial for understanding decay dynamics.
• Feshbach resonance processes provide a theoretical framework for understanding ICD.

Purpose of the Study:

• To investigate the computation of Interatomic Coulombic Decay (ICD) widths using the R-matrix method.
• To assess the accuracy of the R-matrix method for ICD width calculations in a benchmark system.
• To compare R-matrix results with the established Fano-Algebraic Diagrammatic Construction method.

Main Methods:

• Utilized the R-matrix method as implemented in the UKRmol package.
• Employed helium dimer as a benchmark system for computational studies.
• Compared calculated ICD widths with results from the Fano-Algebraic Diagrammatic Construction method.

Main Results:

• The R-matrix method provides accurate total and partial ICD widths for kinetic energies below 10 eV.
• The helium dimer system was successfully used to validate the R-matrix approach.
• The study identified specific energy ranges where the R-matrix method excels.

Conclusions:

• The R-matrix method is a viable and accurate tool for computing ICD widths, particularly at lower electron kinetic energies.
• The findings validate the R-matrix approach for studying complex atomic and molecular decay processes.
• Further discussion on the advantages and limitations of the R-matrix method for ICD computations is provided.