Radiation damage in biological material: electronic properties and electron impact ionization in urea

TL;DR

This study investigates radiation damage in biological materials using urea as a model, focusing on electronic properties and electron impact ionization, combining first-principles calculations with molecular dynamics simulations.

Contribution

It provides a detailed analysis of electron impact ionization and damage distribution in urea, advancing understanding of radiation effects in biomaterials through combined computational methods.

Findings

Quantified damage extent and electron cloud size in urea.

Calculated inelastic electron cross sections from first principles.

Analyzed dependence of damage on initial electron energy.

Abstract

Radiation damage is an unavoidable process when performing structural investigations of biological macromolecules with X-ray sources. In crystallography this process can be limited through damage distribution in a crystal, while for single molecular imaging it can be outrun by employing short intense pulses. Secondary electron generation is crucial during damage formation and we present a study in urea, as model for biomaterial. From first principles we calculate the band structure and energy loss function, and subsequently the inelastic electron cross section in urea. Using Molecular Dynamics simulations, we quantify the damage and study the magnitude and spatial extent of the electron cloud coming from an incident electron, as well as the dependence with initial energy.