Ultrafast radiation chemistry of glycine in aqueous solution

Investigating the ultrafast dynamics of primary biological compounds is crucial to gaininsights on radiation damage. We computationally investigate the ionization-induceddynamics of glycine in an aqueous solution. By employing fewest-switches-surface hoppingsimulations, we specifically address ionization in different orbital levels of the glycinemolecule as well as in water molecules in its solvation shell. Upon ionization, glycineundergoes rapid fragmentation on the Cα -C bond, resulting in the formation of CO2 andthe methylamine (+H3NH2C·) radical. Our analysis shows that the solvation shell has littleeffect on the fragmentation dynamics. When ionized on water, or a deeper valence orbitalof glycine, the system first relaxes to the ground state, involving transfer of the valencehole between water and glycine. The associated redox reaction exemplifies the oxidizingpower of H2O · +.