Nonlinear optical (NLO) properties of the octupolar molecule: Structure-function relationships and solvent effects

Nonlinear optical (NLO) properties of two series of octupolar molecules are investigated to establish the structure-NLO-property relationships by carr ying out the ab initio (HF/6-31G) calculations of the molecular polarizabil ity (a), the first hyperpolarizability (beta), and the second hyperpolariza bility (gamma). II is found that, as the charge-transfer character of the g round state increases by introducing a stronger donor, (i) the absolute BLA value decreases and (ii) alpha, beta, and gamma increase. Thus, the design strategy to maximize the NLO properties of the octupolar molecule is estab lished. Also, the solvation-induced effects on the NLO properties are studi ed by using the self-consistent reaction field (SCRF) method. As the solven t polarity increases, alpha, beta, and gamma increase monotonically. These observations are in good agreement with the predictions based on the valenc e-bond three-charge-transfer model.