Theoretical studies of one- and two-photon absorptions for a series of three-coordinate compounds with different centers (B, Al, N and P) and distyrylbenzenes as branching chromophores

One- and two-photon absorption properties of a series of octupolar molecules with different centers have been theoretically studied with the ZINDO-SOS method. The optimized geometries are obtained by using the ab initio HF/3-21G(d) method, which has been testified good enough to predict the correct geometries for our investigated octupolar molecules. Different centers have important effect on the geometries, one- and two-photon absorptions. The boron (B) and aluminum (Al) act as acceptor centers, while the nitrogen (N) and phosphorus (P) act as donor centers. The calculated results indicate that our investigated molecules are all good candidates for the TPA materials from the view point of transparency-nonlinearity, but Al(DSB) ₃ and P(DSB) ₃ are better than B(DSB) ₃ and N(DSB) ₃. To illustrate the results, the frontier orbitals and net charge changes are analyzed theoretically.