The influence of hydrogen bonding on the nonlinear optical properties of a semiorganic material NH4B[d-(+)-C4H4O5]2·H2O: a theoretical perspective

Abstract

In this work, a potential semiorganic nonlinear optical candidate NH₄B[D-(+)-(C₄H₄O₅)]₂·H₂O (NBC) has been studied using Density Functional Theory. The origin of the second harmonic generation (SHG) effect of NBC crystals for the NH₄B[D-(+)-(C₄H₄O₅)]₂·H₂O molecular complex is explained by employing a combination of the density of states, SHG density and molecular orbital analysis. It reveals a way in which the organic and ammonium groups affect the SHG processes in a significantly different manner in the crystals and the molecular complex. In particular, the role of hydrogen bonding interaction in influencing the electronic structure and nonlinear optical properties is explicitly identified and explained.