Triene Photophysics and Photochemistry: Previtamin D3

Article abstract of DOI:10.1021/ja00216a030

The origin of the wavelenght dependent photochemical behavior of previtamin D₃ was investigated.The fluorescence spectrum and quantum yield of previtamin D₃ were determined at 302 and 307 nm, and both the intensity distribution and the fluorescence quantum yields were found to be independent of excitation energy.A large Stokes shift was observed which is consistent with an excited state torsional relaxation about the central double bond of the triene.The excited state displacement was reproduced by QCFF/PI calculations of the ground and excited states of a model compound.The excited state involved in the absorption and emission spectra is discussed.