Density Functional Theory for the Photoionization Dynamics of Uracil

TL;DR

This study employs advanced density functional theory methods to analyze the photoionization processes of Uracil, revealing site-specific resonances and providing insights that guide future experimental investigations of similar biological molecules.

Contribution

It introduces a novel parallel multicentric DFT approach for calculating the electronic continuum spectrum of Uracil, including both valence and core ionizations.

Findings

Identification of scattering resonances by symmetry and energy

Highlighting site-specificity of core ionization processes

Resonant structures shifted below threshold in photoionization

Abstract

Photoionization dynamics of the RNA base Uracil is studied in the framework of Density Functional Theory (DFT). The photoionization calculations take advantage of a newly developed parallel version of a multicentric approach to the calculation of the electronic continuum spectrum which uses a set of B-spline radial basis functions and a Kohn-Sham density functional hamiltonian. Both valence and core ionizations are considered. Scattering resonances in selected single-particle ionization channels are classified by the symmetry of the resonant state and the peak energy position in the photoelectron kinetic energy scale; the present results highlight once more the site specificity of core ionization processes. We further suggest that the resonant structures previously characterized in low-energy electron collision experiments are partly shifted below threshold by the photoionization processes. A critical evaluation of the theoretical results providing a guide for future experimental work on similar biosystems.