Isomerization of isotopically-labeled benzene13 during free jet expansion

Isotopically-labeled benzene13 clusters, (C6H6)(C6D6)12, were generated by supersonic expansion and studied as a function of nozzle-to-laser distance by resonance-enhanced two-photon ionization (R2PI) spectroscopy through the C6H6 B2u←A1g(601) transition. Because of the spectrumʹs simplicity, it serves as a sensitive monitor of the environment and dynamics of the C6H6 chromophore. We report for the first time evidence for isomerization within this cluster, where the C6H6 moiety migrates from the surface of a rigid cluster to the clusterʹs interior.