The theoretical study of first hyperpolarizabilities of annulene derivatives with different substituted group positions

The molecular first hyperpolarizabilities β and ultraviolet spectra of two-dimensional charge transfer (2DCT) substituted annulenes were calculated by employing TD-DFT approach. It is found that these 2DCT molecules 2∼5 possess larger β values and molecule 3 shows blue-shifted absorption spectra in comparison with the other molecules. It is helpful to solve the nonlinearity-transparency trade-off. For 2DCT molecules 2∼5, values of β depend on the band length alternation (BLA) and when the BLA increases, the values of β decreases. (authors)