Theoretically predicted influence of donors and acceptors on quadratic hyperpolarizabilities in conjugated longhyphen;chain molecules

摘要

The influence of the substitution positions of donors and acceptors on quadratic hyperpolarizabilities (bgr;) was simulated by the AM1 method using four types of conjugated longhyphen;chain molecules having polydiacetylene structures. The chainhyphen;length dependences of bgr; are greatly affected by the molecular type. The molecule, in which donorhyphen;donor pairs and acceptorhyphen;acceptor pairs alternately appear in the chain, has a narrow energy gap of about 1.6 eV and an exceptionally large bgr; per 10 Aring; chain length, about 110 times larger than bgr; of 2hyphen;methylhyphen;4hyphen;nitroaniline.