MOLECULAR FIRST HYPERPOLARIZABILITIES OF RETINAL AND ITS DERIVATIVES

The hyper-Rayleigh scattering technique (HRS) has been used to determi ne the molecular first hyperpolarizabilities beta of retinal, retinoic acid, vitamin A acetate and a retinal Schiff base in its protonated a nd unprotonated form. The former is responsible for the linear and non linear optical properties of bacteriorhodopsin. PI, previous examinat ion of these compounds by HRS at 1064 nm yielded surprisingly high p-v alues. Here, we report HRS measurements performed at 1064, 1300 and 15 00 nm. The derived hyperpolarizabilities are self-consistent with the two-state model for all three wavelengths, but they are one order of m agnitude lower than those reported previously. (C) 1997 Published by E lsevier Science B.V.