A NEW MODEL OF THE 3RD-ORDER NONLINEAR OPTICAL-SYSTEMS WHICH UTILIZES BOTH THROUGH-BOND AND THROUGH-SPACE CHARGE-TRANSFER EFFECTS - POLYMERIC SYSTEMS WITH POLAR SIDE-CHAINS

The third-order organic nonlinear optical systems can be divided into four groups. The criteria of the classification are the symmetry of charge distributions (centrosymmetric and noncentrosymmetric charge distributions) and the types of the interactions which induce the charge-transfer (CT) effects (through-bond and through-space interactions). In this paper we propose the new polymeric systems with polar side chains which are expected to utilize both the through-bond and through-space interactions. The coupled-Hartree-Fock (CHF) method is employed to calculate the third-order hyperpolarizabilities for these systems. The gamma-density analysis is also carried out to obtain the spatial contributions of gamma-values. It is found that the contributions of the side-chain regions are as large as those of the main-chain.