Theoretical and experimental investigation of a pyridinium-based NLO crystal 4-N, N-dimethylamino-4'-N'-methyl-stilbazolium 3,4-dimethoxysulfonate

This study investigates a pyridinium-based NLO crystal 4-N, N-dimethylamino-4'-N'-methyl-stil-bazolium 3,4-dimethoxysulfonate (DOST) containing the strong electron donor, which act the electron and hydrogen bond donors. A DOST signal crystal with a size of 2 x 5 x 1 mm(3) has been grown in methanol solution by the slow cooling growth method. Physical property measurements indicate DOST crystal possesses a strong second harmonic generation response that is 8 times that of KH2PO4 (KDP) crystal and a bandgap of 2.90 eV, making it very promising for nonlinear optical applications. The NLO properties as dipole moment, polarizability, first order hyperpolarizability are performed using density functional theory (DFT) method. Benefiting for the near-perfect alignment of DOS cations, DOST crystal exhibits a large diagonal component of the effective hyperpolarization, about 105.21 x 10(-30) esu. Furthermore, information about the sites of intermolecular interaction has been obtained by molecular electrostatic potential (MEP) surface and Hirshfeld Surface. In order to understand the electronic properties, the absorption wavelengths, excitation energies, oscillator strength, the frontier molecular orbitals and global reactivity descriptors are also calculated.