Electron and positron collisions with molecules of biological relevance

Ionizing radiation can damages living organisms by breaking cell constituents, for example, DNA. Electrons with energy below 20 eV are known to cause these breaks via the formation of temporary negative ions or resonances. Using the R-matrix method and the UKRmol+ suite, we investigate the interaction of low energy electrons with biomolecules or their precursors. The aim is to understand resonance formation, the first step in low-energy electron induced damage, as well as determining accurate cross sections that are used in the modelling of radiation damage.

Positrons (the antipartcile of electrons) are used in Positron Emission Tomography (PET) for medical imaging. We calculate cross section data on their interaction with biomolecules needed to model the effect of PET on the body.

Environment mediated and enhanced electron induced processes

In many applied fields, electron-molecule collisions take place in environments such as bulk matter and surfaces. This environment can affect the and its outcome. In addition, it can lead to intereting new processes like Interatomic Coulombic Electron Capture (ICEC) where an electron is trapped by a molecular cation and, via energy transfer, cause the ionization of a different nearby molecule. We study electron scattering from small clusters to: (a) understand how microhydration affects resonance formation; (b) provide quantitative information and fundamental insight into ICEC. (Here's an explanation of ICEC made from gingerbread by Vincent Graves.

AMO Software development

Atto-second laser-matter interactions, radiation damage, etc. are processes in which correlated multi-electron dynamics play a signficant role. Calculations that accurately describe these multi-electron interactions usually require the use High Performance Computing. We develop the UKRmol+ suite, part of a suite of high-quality computer codes (UK-AMOR) to study electron, positron and photon interaction with polyatomic molecules. The suite also provides input for RMT, a code for time-dependant calculations of molecular photoionization . The software development is coordinated more broadly by the UK-AMOR High-end Computing Consortium and CCPQ.