Femtosecond X-ray Scattering as a Spatiotemporal Probe of Chemical Reactions in Isolated Molecules

Program Description

In order to relate our understanding of electronic surfaces to structural dynamics of isolated molecules, a full observation of electronic and nuclear motions during reactions is necessary.  Within the last two years, experiments at the Linac Coherent Light Source (LCLS) have allowed us to develop and implement an experiment wherein the ultrafast reaction dynamics of molecules in dilute gases is captured by time-resolved X-ray scattering.  In this experiment, 1,3-cyclohexadiene is prepared in an excited electronic state, which causes the molecule to accelerate down several potential energy surfaces coupled by conical intersections to open into 1,3,5-hexatriene within 80 fs, from which the structure continues to move toward its lowest energy conformer.