Influence of pi-stacking on the resonant enhancement of the second-order nonlinear optical response of dipolar chromophores

The use of second-harmonic generation at different wavelengths to compare the resonant contributions of two simple dipolar chromophores, nitroaniline and nitrosulfenamide is reported. The result shows that pi intermolecular interaction does result in excitations that are observable in the linear spectrum of nitroaniline and thus could have an influence on the nonlinear response.