Theoretical Studies on the Nonlinear Optical Properties of Octupolar Tri-s-triazines.

The first-, second-, and third-order static and frequency-dependent polarizabilities of a series of octupolar tri-s-triazines have been investigated by using the ab initio coupled perturbed Hartree-Fock (CPHF) method. Effects of substitution have also been considered. The results show that α, β, and γ values for octupolar tri-s-triazines are much larger than those for s-triazine in both static and frequency-dependent cases. Attaching groups containing π systems such as azide and ethenyl to the tri-s-triazine molecule results in a significant increase of first-, second-, and third-order polarizabilities. Our calculations suggest that the octupolar tri-s-triazines may be prospective candidates for nonlinear optical materials.