Harmonic rayleigh scattering from nonlinear octupolar molecular media: the case of crystal violet

摘要: Abstract Experimental evidence is provided to supplement earlier molecular engineering propositions as the high nonlinearities of octupolar origin. The absence dipole moment in such structures precludes utilization electric-field-induced second-harmonic generation (EFISH) solution: harmonic light scattering (HLS), which does not require dipolar electric field poling, shown provide quantitative access quadratic nonlinearity nonlinear molecules. Crystal violet, a trigonal conjugated cationic dye with electronic charge transfer from peripheral dimethylamino donor groups an electron deficient sp 2 hybridized central carbon atom, chosen illustrate relevance HLS this context well experimental estimate β magnitude prototypical system. A resonantly enhanced value 580 × 10 −30 esu found at 1.064 μm, acetone solution (λ max = 590 nm). Due care taken solvent calibration while detailed account symmetry considerations and tensorial averaging are for various point (D 3 , D 3h C 2v T d ). It that besides exploration new family systems, experiment should be also used revisit more traditional systems: it complements EFISH experiments providing measure anisotropy hyperpolarizabilities.