Sub-picosecond C<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mo>=</mml:mo></mml:math>C bond photo-isomerization: evidence for the role of excited state mixing

Sub-picosecond photo-isomerization is the major primary process of energy conversion in retinal proteins and has as such been focus extensive theoretical experimental work over past decades. In this review article, we revisit long-standing question to how protein tunes isomerization speed quantum yield. We on our recent contributions field, which underscore concept a delicate mixing reactive non-reactive excited states, result steric properties electrostatic interactions with environment. Further avenues new approaches are outlined hold promise for advancing understanding these intimately coupled chromophore–protein systems.