TWO-PHOTON EXCITATION SPECTRA OF RETINYL POLYENES IN RANDOM GLASSES
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Date
1977
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Ohio State University
Abstract
Two-photon excitation spectra of several retinyl polyenes (all-trans retinol, all-trans retinal and all-trans anhydrovitamin A), and of diphenyloctatetraene in random glass matrices at $77^\circ K$ have been obtained in the energy region 10 000--14 000 $cm^{-1}$. A ruby laser-pumped tunable dye laser was used as the excitation source. The presence of two-photon, allowed, electronic bands in all of these linear polyenes, at energies below the strongly allowed one-photon, absorption to the lowest $1_{B_{u}}$ state, has been established. A possible assignment for the upper state is $1_{A_{g}}$, to which one-photon transitions from the ground state would be symmetry forbidden. The location of this low energy transition removes several discrepancies between the expected and observed fluorescence properties of these polyenes.
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Author Institution: Department of Chemistry, Michigan State University