Evaluation of Electronic, Optoelectronic, and Nonlinear Optical Responses in Functionalized Pyrazine Chromophores: A Density Functional Theory Study

The development of efficient nonlinear optical (NLO) materials plays a pivotal role in advancing optoelectronic technologies. In this work, the electronic structures and NLO properties of newly designed pyrazine (PZ)‐based derivatives (PZR and PZD1‐PZD6) were explored through density functional theory (DFT) and time‐dependent DFT (TD‐DFT) approaches, utilizing the B3LYP/6‐31G(d, p) level of theory. The calculated energy gaps ( E gap ) between the HOMOs and LUMOs of these compounds ranged from 1.309 to 1.589 eV, with PZD2 derivative demonstrating the lowest‐energy gap (1.309 eV) of all compounds. Furthermore, the visible spectra of the investigated chromophores exhibited the highest λ max values (535–700 nm), indicating strong absorption in the visible region. In addition, natural bond orbital analysis has also confirmed the stability of compounds. Overall, the designed chromophores demonstrated excellent NLO characteristics, validating their potential as promising candidates for optoelectronic applications. Among all designed derivatives, PZD2 is the leading compound due to its maximum dipole moment (1.94 × 10 −17 D) along with improved first hyperpolarizability (1.68 × 10 −27 esu) and second hyperpolarizability (3.45 × 10 −32 esu). These findings suggest that the incorporation of these groups enhances the performance, making these compounds strong candidates for experimental validation in future NLO applications.