Assessing the dipolar-octupolar NLO behavior of substituted thiosemicarbazone assemblies

Abstract

Density Functional Theory with hyper-Rayleigh scattering is used to investigate the non-linear optical response of newly synthesized thiosemicarbazone molecules. The systems present low refractive indices, and PDOS analyses indicate that the substituents chlorine and bromine induce a batchromism in the UV–Vis spectra and significantly improve (ca. 69%) the estimate of the first hyperpolarizability (βHRS) to values fifty times higher than those reported for urea (β=0.34×10−30 esu). Moreover, intramolecular charge transfer processes and evident octupolar contributions (ΦJ=3≈70%) account for the NLO behavior. The results suggest potential uses in optoelectronics and photonics.