PHYS 7 |
| A combination of experimental and computational analysis is used to provide a more complete understanding of the molecular level origin of the unique photophysical properties of three benzophenone derivatives used in sunscreens: oxybenzone, dioxybenzone, and sulisobenzone. Experimentally, electronic transitions are examined in a variety of solvents. There are significant differences in the solvatochromic behavior of the three systems. The spectral trends do not appear to originate from only changes in the solvent polarity, but indicate that specific solvent-solute interactions influence the absorbance of some benzophenones. Computational investigations examine the structure of the isolated chromophores and proposed solvent-solute complexes. Excitation energies are calculated for all structures and complexes to determine the role complexation plays on the electronic transitions, and to analyze the molecular orbitals involved in spectroscopically observed transitions. Excited state proton transfer is proposed as a deactivation mechanism following photoexcitation, and the energetics of this process are examined theoretically. |
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Computational Spectroscopy
8:00 AM-12:05 PM, Sunday, April 6, 2008 Morial Convention Center -- Rm. 342, Oral
Division of Physical Chemistry |