Observation of conformer-specific photochemical dynamics with MeV ultrafast electron diffraction

We investigated the ultrafast photochemical ring-opening in the molecule α-phellandrene by a combination of megaelecronvolt ultrafast electron diffraction and excited state ab initio multiple spawning wavepacket simulations. α- Phellandrene exhibits a number of different conformers which produce different ring-opening photoproducts according to the Woodward-Hoffmann rules. In our study we image the conversion of a specific conformer of α-phellandrene in the Woodward-Hoffmann predicted photoproduct in real time and space.