LUMIERE · Liquid phase Ultrafast photoeMIssion spEctroscopy of nonadiabatic photoREactions in biomimetic systems

The chromophores of photo-responsive proteins (PRPs) are increasingly exploited in science and technology from time and spatially resolved studies of neural signaling to the engineering of fully synthetic molecular devices. This justifies the increasing need for interdisciplinary studies aiming at controlling the chromophore function and achieving novel applications. In this doctoral network we will combine design, preparation and theory of PRP chromophores operating as rotary molecular-level devices with the novel tool of time-resolved photoemission spectroscopy (TRPES) to unravel basic principles of their rotary function.The most prominent PRPs, e.g. retinal proteins, the green fluorescent protein or xanthopsin all convert the photon energy into rotary motion by leveraging efficient ultrafast double-bond isomerizations. There is a consensus that such energy conversion is mediated by conical intersections (CIs) between ground and excited state potential energy surfaces. TRPES is a novel method, emerging at the interface of ultrafast physics and chemistry, capable of imaging the dynamics through CIs, thus providing a unique view on thephoton-to-nuclear-rotation transduction process. More specifically, novel TRPES tools developed within the network will be employed to study devices based on oxindoles and oxipyrroles, mimicking the green-fluorescent protein chromophores, and on cinnamic ester derivatives, mimicking the chromophores of xanthopsins. We will investigate and learn to control these systems studying selected sets of chemical substitutions and environmental effects.The development of an effective research protocol focused on the combination of novel syntheses, TRPES and interpretative state-ofthe-art quantum chemical methods, will provide a cutting-edge interdisciplinary training arena for talented doctoral students and will be complemented by a modern soft-skill learning program and intense knowledge exchange between science and industry.