Spectroscopic investigation, nucleation, growth, optical, thermal and second harmonic studies of novel semi-organic nonlinear optical crystal - thiourea urea zinc sulfate.

A new nonlinear optical crystal thiourea urea zinc sulfate (TUZS) has been grown by slow evaporation technique in equimolar ratio. Solubility and metastable zone width measurements have been determined for the grown crystal. Single crystal XRD revealed that the crystal system belongs to orthorhombic with cell parameters a=7.78Å, b=11.15Å and c=15.47Å. The sharp and well defined Bragg peaks observed in the powder XRD pattern confirm the crystalline nature of the TUZS compound. The grown mechanism and surface features were investigated by optical microscopic techniques such as scanning electron microscopy (SEM). The presence of zinc in the grown crystal was detected by atomic absorption spectroscopy and EDAX analysis. The compound has been confirmed by (1)H NMR, mass and FTIR spectral studies. The transmittance spectrum of TUZS has been used to calculate the extinction coefficient K, reflectance R, as functions of photon energy. The optical band gap of TUZS is 4.046 eV. The SHG efficiency has been tested by the Kurtz powder technique using Nd: YAG laser and KDP sample has been used as a standard reference material.