Photochemistry — 6 is a collection of plenary lectures presented at the Sixth International Symposium on Photochemistry held in Aix-en-Provence, France, on July 19-23, 1976. Contributors focus on the photochemistry of a variety of compounds and substances, including bichromophoric compounds, heterocycles, and metal carbonyls. The results of photochemical studies of visual pigments are also presented. This book is comprised of 14 chapters and opens with a review of the state of the art of ab initio quantum-mechanical calculations for polyatomic molecules, with particular reference to predictions of interest to photochemists. The major areas discussed are spectral predictions, substituent effects on energy gaps, and potential energy surfaces. The following chapters explore energy transfer and molecular mobility in polymer photochemistry; the photochemistry of polyenes and aromatic-N-ylides; cis-trans isomerization in the photochemistry of vision; and aromatic aldehyde-leuco dye photoxidation. The electrochemical boundaries for the photochemistry of spectrally sensitized silver halide emulsions are also examined, along with the photochemistry of organic chromophores incorporated into fatty acid monolayers. This monograph will be of interest to chemists in general and photochemists in particular.