Color Prediction of Photochromic Organic Compounds: Theoretical Calculations of Ground and Excited States of Spiropyrans, Spirooxazines and Diarylnaphthopyrans

ab initio and semi-empirical geometry optimization in conjunction with modified CS-INDO-CIPSI calculations was performed to predict the λmax of absorption of merocyanines forms of spiro[indoline-naphthoxazine], spiro[indoline-naphthopyran] and diarylnaphthopyrans. The predicted λmax are found in excellent agreement with experimental values providing the geometry used for vertical energies calculation is delocalized, i.e. obtained at the UHF/AM1 and DFT levels.