Abstract:

In This paper some problems, which should be noticed in the measurements of organic molecular first hyperpolarizability（β） by the solvatochromism , are discussed based on the results of the measurements for 11 compounds .The experiments indicate the at the selection of solvent used is the basis of the method to fit for use. The determination of the parameter a, which is the radius of a spherical cavity occupied by the molecules in the solutions, is the key to decide the reasonableness of the obtained results and the formula for a=1/2(l'+rv),has been suggested in which l is the molecular length of the nonlinear optical active part and can be obtained from values of bond lengths in literature, rv is the average spherical radius of used solvents.

Key words: Organic nonlinear optics, Molecular first hyperpolarizability(β), Solvatochromism