Linear and Hyperpolarizabilities of Spiropyran and Derivatives

The geometry of spiropyran molecule and its derivatives was found using quasi-Newton methods, Broyden-Fletcher-Goldfarb-Shanno technique. Then ab initio quantum chemical methods were applied to calculate the ground state energies of the closed and open forms of spiropyran for different basis sets. The frequency dependent linear polarizability of spiropyran and derivatives were obtained and plotted. The found absorption peaks are different for the closed and the open structures of the spiropyran molecule.