A computational study of the non-linear optical properties in π-σ-π coupled donor-acceptor organic molecules

First hyperpolarizabilities (beta) are calculated using semi-empirical molecular orbital methods for some organic molecules containing pi-electron-donor (D) and pi-electron accepters (A), and separated by saturated sigma-bonds. Intramolecular charge transfer between D and A is observed and the molecules show large beta. These molecules are predicted to have more transparency in the region of interest for frequency doubling applications. This study suggests that these saturated bridges in general may have potential applications in the development of non-linear optical materials.