The electronic structure, UV-vis spectrum, nonlinear third-order optical susceptibility and dispersion of phthalocyanine(H2Pc) and copper phthalocyanine(CuPc) were studied by using INDO/SDCI method. It was discovered that the contribution of Cu2+ ion to g is very little in CuPc, so the g of CuPc is almost equal to g of H2Pc. It can be explained reasonably from the authors' calculated results.

Key words: OPTICAL PROPERTIES, QUANTUM CHEMISTRY, DYES, ELECTRONIC STRUCTURE, PERTURBATION THEORY, NON LINEAR OPTICS, INTERMEDIATE NEGLECT OF DIFFERENTIAL OVERLAP APPROXIMATION (IND, THIRD DERIVATIVE, ZINC PHTHALOCYANINE, PHTHALOCYANIN (=PHTHALOCYANINE)