Electronic structures of asymmetrically substituted phthalocyanines and their second non-linear optical properties

Quantum-chemical AM1 calculations were performed to study the geometries, t he electronic structures and the second nonlinear optical properties of pht halocyanine and some asymmetrically substituted phthalocyanines, which incl ude tert-butyl, amino, dimethylamino, nitro, fluoro, chloro, bromo, iodo an d nitrile substituents. The relationships of the second non-linear optical coefficients beta with dipole moment mu, and beta with the energy-gap diffe rences of frontier orbitals DeltaE(DA) were discussed. Two relationships ar e regular and all DeltaE(DA) - mu show very good linear relationship.