Theoretical study of solvent modulation of the first hyperpolarizability of PNA, DNBT and DCH

The solvent modulated first hyperpolarizabilities (beta (mu)) of p-nitroani line (PNA), 5-dimethyl aniino-5'-nitro-2,2'-bithiophene (DNBT) and 1,1-dicy ano-6-amino-hexatriene (DCH) are studied by semiempirical finite field SCF method under the scaled self-consistent reaction field (SSCRF) model of sol vation recently proposed by us. Simultaneously, the two-state optical model is invoked to calculate the static solvent modified beta ( = beta (0)), us ing SSCRF energies. beta (mu) is directly comparable with the EFISH results in solution while go values refer more closely to what is obtained in hype r Rayleigh scattering (HRS) measurements. Appreciable changes in both beta (mu) and beta (0) are predicted to occur as function of solvent polarity. ( C) 2001 Elsevier Science B.V. All rights reserved.