Theoretical calculations of molecular dipole moment, polarizability, and first hyperpolarizability of glycine-sodium nitrate

In order to calculate the energy gap, molecular dipole moment, polarizability, and first hyperpolarizability of glycine-sodium nitrate (Na(NO₃)·C₂H₅NO₂), a series of basis sets including polarized and diffuse functions have been employed at the framework of: Hartree-Fock, Density Functional Theory, and Möller-Plesset Perturbation Theory methods. Geometry optimization was carried out with DFT-B3LYP 6-311++G(d,p). The geometrical differences between the optimized molecule and the molecule in solid phase were attributed to intramolecular and intermolecular forces that are present in solid phase. In addition, the results have revealed that hydrogen bonds not only play an important role determining the crystal structure of glycine-sodium nitrate but also decreasing its energy gap. Further, it was confirmed that glycine-sodium nitrate has absolute value of dipole moment which is mainly caused by both the glycine dipolar character and the molecular geometry. Likewise, the calculations gave non-zero values of polarizability and first hyperpolarizability which are related to the linear and nonlinear responses, respectively.