Investigation of Some Photochromic Structures by Molecular Mechanics and Scf Mo Calculations

In order to predict the geometry and electronic spectra of spiropyrans and spirooxazines, the validity of some semi-empirical methods has been checked. Results show that both AM1 and GenMol give reasonable geometrical values. If CNDO/S and INDO/S calculate well theoretical absorption of closed forms, in contrast, the Δmax obtained for opened forms are underevaluated.