From Radiation to Radicals: X-ray-Induced Dynamics of Free and Solvated Systems Containing Heavy Atoms

Project title: From Radiation to Radicals: X-ray-Induced Dynamics of Free and Solvated Systems Containing Heavy Atoms
Main applicant: Olle Björneholm, Divison of Molecular and Condensed Matter Physics
Grant amount: 3 300 000 SEK for the period 2017-2021
Funder: Project grant from the Swedish Research Council

Project description

Understanding x-ray radiation damage is a crucial issue for medical applications of x-rays, as well as for x-ray free-electron-laser science aimed at molecular imaging. Biomaterials mostly consist of low-Z atoms, but high-Z atoms contribute more to radiation damage than their concentration suggests, due to their higher ionization cross section. The first steps in radiation damage involve x-rays ionizing deep core levels, which will rapidly decay. The main aim of the proposed project is to explore the x-ray-induced electronic and nuclear dynamics in simple systems containing heavy atoms, both in gas phase and in solution. Synchrotron radiation will be used to photoexcite and photoionize such systems in the photon energy range 2-13 keV. The goals are to reach a very detailed picture of what happens when a molecule is irradiated by an x-ray photon (chemical bond breaking, change of geometry, photodissociation, charge transfer, etc.), with consequences in many fields such as chemistry of the upper atmosphere, environmental problems, detailed description of photochemical reactions, etc.; to study in great detail the effect of water solvation by comparing similar processes for the same heavy atoms in isolated species or in solution; to obtain a deep insight into the electronic and nuclear dynamics from deep core-hole creation in solvated species over intermolecular decay cascades to formation of radicals; to study first steps of radiation damage in simple biomolecular model systems.