General Physics Colloquium 'Molecular resonances and ultrafast dual photoresponse of anionic biochromophores' Anastasia Bochenkova IFA The functioning of light-sensitive proteins is closely connected to the ways, by which the protein environment tunes the intrinsic photoresponse of their chromophores and guides their excited state evolution. Recently, we have disclosed a striking fundamental interplay between electronic and nuclear dynamics in competing excited-state decay channels of the anionic Green Fluorescent Protein (GFP) chromophore. A non-adiabatic nature of the excited-state dynamics unexpectedly results in co-existing mutual energy-borrowing mechanisms between nuclei and electrons. By combining a novel time-domain approach to action spectroscopy and a highly correlated multi-reference electronic structure theory, we show that the energy exchange is fast and, importantly, mode-specific. The de-excitation includes vibrationally assisted electron emission out of the first excited state and internal conversion back to the hot ground state, where the latter is shown to proceed through the two distinct types of conical intersections. The mode-specificity paves the way to a control of the branching ratio in the GFP chromophore, which has been demonstrated experimentally, and, ultimately, to a mode-selective photochemistry and photophysics of the GFP proteins. Wine and cheese will be served at 4 PM