Computational studies of photoactive ionic molecular systems: Investigating the effect of protonation and deprotonation on the excited states of molecular systems of key photochemical interest

This project has been funded through apeer reviewed application to the EPSRC NSCCS service:
Award: 9,910 CPU hrs
Abstract:
One common feature of many of important photoactive molecules (e.g. commercial sunscreens, plant sunscreen molecules and photochromic antioxidants) is that they are able to transfer UV radiation absorbed, via ultrafast decay, back to the electronic ground state followed by dissipation of this excess energy as heat. Typically, the ultrafast decay involves internal conversion via a barrierless hydrogen atom transfer. This leads to questions about the extent to which a photochemically active molecule can be affected by protonation and deprotonation, an issue that has been largely ignored to date in gas-phase experiments. We propose to investigate this issue by conducting gas-phase laser spectroscopy experiments on a range of key photochemical molecules, in their charged protonated and deprotonated forms. In this project, we will perform calculations on the systems listed above to aid the interpretation of recently acquired spectra, and also to support future planned work in this area.