How bromoform wrecks ozone: Ultrafast 'roaming' step captured in 150 femtoseconds

The halomethane compound bromoform (CHBr3) has devastating effects on the ozone layer. In the upper layers of the atmosphere, bromoform reacts with UV radiation, releasing bromine molecules which destroy ozone molecules. This reaction, however, has long puzzled scientists; the molecules involved seem to wander relative to each other in a way that energetically does not make sense. Scientists at European XFEL have now revealed structural evidence for this roaming mechanism for the first time, establishing it as a universal characteristic of photochemical reactions.