text: Schulten received a Diplom degree from the University of Münster in 1969 and a PhD in chemical physics from Harvard University in 1974, advised by Martin Karplus. At Harvard Schulten studied vision, and the ways in which biomolecules respond to photoexcitation. He was particularly interested in studying retinal, a polyene and a chromophore of opsins. Schulten was able to provide a theoretical explanation for experimental observations of an "optically forbidden" state which did not match predicted patterns of electronic excitation in polyenes. Schulten classified electrons into covalent and non-covalent states, and determined that electrons that acted in a coordinated (covalent) manner used less energy than those which were independent (non-covalent).