Femtosecond UV photochemistry of the biologically relevant L-cysteine disulfide moiety in aqueous solution investigated by time-resolved X-ray absorption spectroscopy

Femtosecond X-ray absorption spectroscopy of the disulfide bridge in L-cystine reveals the thyil radical as the only primary photoproduct which geminately recombines in an ultrafast solvent cage-mediated process, leading to the long-lived perthyil radical.