Theoretical studies on molecular structure and vibrational spectra of copper phthalocyanine

Density functional theory (DFT) calculations have been used to predict the geometry structure and vibrational spectra for copper phthalocyanine (CuPc). The calculated results of structure and frequency are very good agreement to the experimental values. The scientific method for analyzing vibrational spectra of complicated molecule is established herein by giving main fixed points and pivotal vibrational units in assignment for each fundamental band. Two new symbols η (heaving along the specified direction) and M (barycenter of a bond or unit) are defined for describing the vibrational modes accurately.