SEMIEMPIRICAL CALCULATIONS OF MOLECULAR POLARIZABILITIES AND HYPERPOLARIZABILITIES OF POLYCYCLIC AROMATIC-COMPOUNDS

The correlation of 2D conjugation and the nonlinear properties of a series of polycyclic aromatic compounds were studied by performing semiempirical calculations using the MOPAC package. For linear polyacenes, both linear and nonlinear properties are found to be increased as the number of six-membered rings increases. In general, the polarizabilities, [alpha], and second hyperpolarizabilities, [gamma], are found to correlate very well with total resonance energies. In the case of first hyperpolarizabilities, [beta], symmetry is the dominating factor.