Mode-selective photoisomerization in 5-hydroxytropolone. I. Experiment

摘要: Laser‐induced fluorescence excitation, dispersed fluorescence, and population labeling spectra of the S0–S1 transition 5‐hydroxytropolone (5‐HOTrOH) have been recorded in a supersonic free jet. In ground state, two in‐plane orientations 5‐OH substituent produce isomers, syn anti relative to 2‐OH. Population is used identify transitions spectrum originating from zero‐point levels. excited electronic state where 2‐OH H‐atom tunneling expected be more facile, single vibronic level levels with widely varying syn–anti character. Many low‐energy region are nearly pure or character, thereby showing little coupling isomerization reaction coordinate. Other strongly mixed via Fermi resonance interactions. A few exhibit strong mixing despite being relatively isolated other These...