Theoretical studies on nonlinear optical properties of two newly synthesized compounds: PVPHC and DPVPA

The nonlinear optical properties of two newly synthesized molecules 9-(4-{2-[4-(2-pyridin-4-yl-vinyl)-phenyl]-vinyl}-phenyl)-9H-carbazole (PVPHC) and diphenyl-(4-{2-[4-(2-pyridin-4-yl-vinyl)-phenyl]-vinyl}-phenyl)-amine (DPVPA) have been studied using hybrid density functional theory at B3LYP level. A few-state model, as well as response theory, have been employed to calculate their two-photon absorption cross-sections. The theoretical results are in good agreement with the experimental measurements available. It is found that the maximal two-photon absorption cross-sections of these compounds can be well described by a three-state model and both compounds have large two-photon absorption cross-section in optical regime. Strong charge-transfer process upon excitation has been revealed, indicating that these two compounds are good candidates as two-photon polymerization initiators.