Experiment records ultrafast chemical reaction with vibrational echoes

To watch a magician transform a vase of flowers into a rabbit, it's best to have a front-row seat. Likewise, for chemical transformations in solution, the best view belongs to the molecular spectators closest to the action. Those special molecules comprise the "first solvation shell," and although it has been known for decades that they can sense and dictate the fate of nearly every chemical reaction, it has been virtually impossible to watch them respond -- until now.