This grant from the Organic Dynamics Program supports the continuing work of Dr. Jack Saltiel at Florida State University. Knowledge gained from this research will provide an improved understanding of complex light-initiated phenomena such as the visual process. Dr. Saltiel's research will focus on the photochemistry of olefins, arenes, and aromatic ketones. The major area will be a detailed study of olefin photoisomerization, including the effects of solvent polarity, the mechanism of nonvertical triplet and singlet energy transfer, and the use of conformationally rigid analogs to evaluate ground state conformational control of the photochemical and photophysical events. Principal component analysis with self-modeling will be employed to resolve complex spectra into the contributions of individual conformers.