Sub-7-femtosecond conical-intersection dynamics probed at the carbon K-edge

How fast is electronic relaxation? Technical advances in extending spectroscopy to the attosecond time scale has caused considerable interest experimental studies of various ultrafast processes that were previously inaccessible. Using transient absorption around carbon K-edge accompanied by ab initio quantum dynamics simulations, Zinchenko et al. investigated ultrafast, non-adiabatic ethylene cation. They directly observed D 1 ? 0 relaxation mediated conical intersection taking place within 7 femtoseconds, far shorter than any vibrational period or reported relaxation. The demonstrated technique applicable liquids and solutions, enabling further charge- energy-transfer organic molecules chemical biochemical systems. Science , this issue p. 489