FIRST HYPERPOLARIZABILITY OF THE HETEROCYCLIC SULFONAMIDES FOR LANGMUIR-BLODGETT-FILMS BY CALCULATION, SOLVATOCHROMISM, AND HYPER-RAYLEIGH SCATTERING

The first hyperpolarizability beta of n-alkanamides of 4-amino-N-(thia zol-2-yl)benzesulfonamide (A) and 4-amino-N-(pyrimidin-2-yl)benzenesul fonamide (B) was evaluated by ab initio (Gaussian, GAMESS) and semiemp irical (INDO1/S) calculations. The results obtained at the ab initio l evel showed that the values of beta of the chromophores were 3.5-4 tim es that of p-nitroaniline. The calculations by INDO1/S gave preference to A and in absolute scale the beta values were 104.6 and 90.9 x 10(- 40) m(4)/V for A and B, respectively, and they were slightly lower tha n those from ab initio. Fluorescence solvatochromism and hyper-Rayleig h scattering (HRS) was applied to determine experimentally the first h yperpolarizability of two amphiphiles containing n-hexadecanoyl (A) an d n-decanoyl (B) radical. The values of beta obtained by the fluoresce nce solvatochromism were in the same range for A and B, and were (94-1 00) x 10(-40) m(4)/V while the HRS procedure gave preference to B yiel ding 252.1 and 197.8 (at 1064 nm), and 113.1 and 88.8 (static) for B a nd A, respectively (all in x 10(-40) m(4)/V). The role of the heterocy clic ring of the chromophore molecule in the electron donating-accepti ng process was shortly discussed.