Hyperpolarizabilities of substituted polyphenyls

The dipole axis diagonal components of static polarizability alpha, first-order hyperpolarizability beta and second-order hyperpolarizability gamma of a series of push-pull polyphenyls are calculated via a simplified sum over states (SOS) technique based on ab initio Hartree-Fock (HF) data with the 6-31G** basis set. Additional calculations on similar molecules at the same level of theory are performed to help the analysis of results. An explanation is provided for the behavior of the dipole and the three polarizabilities with respect to the increasing molecular size. The role of molecular structure and interactions is analyzed. A new formulation for the simplified missing state analysis is proposed.