Physicochemical factors that enhance the third order nonlinear susceptibility χ(3) in nitroanilines and conjugated polyenyne polymers with arylamine substituents

Abstract

This work analyzes the physicochemical factors that improve the χ(3)-NLO properties based on Hückel-Agrawal’s model. The model compounds are the nitroanilines ortho o-NA, meta m-NA, and para p-NA, and the aromatic polyenynes with phenyl and an NH2 group in position ortho, meta, and para, or without the amine group. We analyze the correlation effects, the dipole moments, the resonance energy, the frequency of the laser wavelength, the interband and intraband effects, the charge density, the curvature of the dipole moments, and the vibration phononic factor in addition to the molecular effects proposed by Nalwa’s work. Then, we have found, for example, that the addition of a conjugate chain to the nitrogen of the amine, the continuity of the same sign of charge in the valence band, which produces electric repulsion, or the increase in the spatial asymmetry of the groups attached to the aromatic ring can increase the χ(3) values.