Honours Project

This goal of this project will be to understand factors mediating the efficiency and speed of photoconversion in spiropyran-merocyanine photoswitches.  These molecules are interesting because the switching process is reversible, and because the reactant and product forms have very different dipole moments (see attached figure) and optical properties.  They are useful as photochromic switching media in organic photonic materials, and have also been used to drive conformational changes in modified proteins!

The project will involve the application of state-of-the art quantum chemistry to characterize the electronic states involved in the photoreaction and the conical intersections between the respective surfaces.  Nonadiabatic quantum molecular dynamics simulations will be used to uncover the key dynamical parameters controlling the speed of the photoreaction and the photochemical branching ratios. the ultimate goal will be to distill the computational data into a lucid few-body quantum mechanical model that can be used to formulate structure-property relationships for experimental testing and for optimization of the photoswitching properties of these molecules.  A secondary goal will be to formulate an empirical valence-bond model that can be used to simulate the photoconversion in the context of molecular dynamics simulations of photoswitch-protein complexes.

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