Strong electron correlation effects on first- and second-order hyperpolarizabilities in zwitterionic sigma-conjugated systems: its dependence on substituents, conformations, spacer size, and basis sets.
Nonlinear optical properties of zwitterionic sigma-conjugated systems were theoretically investigated with relation to the electron correlation effects at the ab initio molecular orbital level. We examined the strong electron correlation effects on the first- and second-order hyperpolarizabilities in the specific systems with effective "pi-sigma-pi" and (or) "pi-sigma-n" interactions. The electron correlation effects on the hyperpolarizabilities strongly depend on the type of substituents, conformations, spacer size, and basis sets. It was found that the Hartree-Fock level calculations qualitatively predict the behavior of the hyperpolarizabilities after considering the correlation effects. Through-space/-bond interaction analysis quantitatively revealed that the electron correlation effects on the hyperpolarizabilities were induced mainly by the sigma-conjugations on the spacer unit in the zwitterionic sigma-systems.
Orimoto
Yuuichi
Y
Department of Material Sciences, Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-Park, Fukuoka 816-8580, Japan.
Aoki
Yuriko
Y