Theoretical investigation on two-photon absorption properties of (dicyanomethylene)-pyran derivatives

Based on DCM structure moiety, we have designed a series of symmetric (dicyanomethylene)-pyran derivatives in which benzene rings were replaced by thiophene rings. Their two-photon absorption (TPA) properties were studied by using a combination of intermediate neglect of differential overlap Hamiltonian with the configuration interaction technique combined with sum-over-states expression. The calculated results show that the TPA cross-sections are sensitive to molecular structure. The electron excessivity of heterocycle and double-bridge effect on TPA cross-sections is discussed. (C) 2001 Elsevier Science BN. All rights reserved.