Theoretical Study on Nonlinear Optical Properties of the Substituted Coumarin Derivatives

The β values of a series of coumarin derivatives were calculated by using CNDO/S-CI program.The result reveal that this kind of compounds have fairly second order polarizabilities.The structure dependence of the nonlinear optical properties was studies.It was considered that the place and classification as well as the enumerating of substituted effect the values of β.The bulk of substituted was considered that it is important factor of influence on second order polarizabilities.Morver,there must be a close relation between the best structures and the highest values of β. By studing relationship of the stuctures of a series of coumarin derivatives and second order nonlinear optical microproperties,we confirm that this kind of compounds be a sort of high-quality organic nonlinear optical materials.It was well worth studing for further.Among these compounds,7-hydroxyl-4-methylcoumarin and 7-nitro-4-methylcoumarin both have higher β values.