| Popis: |
The initial dynamics in the photoisomerization of cis-stilbene, especially the dynamics leading to photocyclization, is explored by studying the high-resolution spectroscopy and implied dynamics of a series of 1,2-diphenylcycloalkenes. These molecules are isochromophoric to cis-stilbene but are structurally hindered from undergoing cis-trans isomerization. In particular, the high-resolution fluorescence excitation spectrum of 1,2-diphenylcyclobutane (DPC-4) reveals detailed information about the symmetric in-plane bend and symmetric phenyl ring twist motions, which are crucial to photocyclization. The DPC-4 spectrum is analyzed theoretically, and an empirical surface is constructed for the S 1 state that reproduces both line positions and relative intensities in the observed spectrum. Evidence for the importance of photocyclization in the dynamics of excited state cis-stilbene is presented and discussed |
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