Synthesis, Characterization, Thermal Analysis, Nucleation Kinetics and DFT Studies of Bis(thiourea) Antimony Tribromide as Potential NLO Material: Comparison of Experimental and Computational Studies

Abstract

Semi organic non linear optical single crystals of bis (thiourea) antimony tribromide (BTAB) have been grown and harvested using slow solvent evaporation technique. The single crystal X-ray diffraction analysis indicated the orthorhombic and non centrosymmetric nature of the title compound. The powder XRD and High resolution XRD patterns pronounced the crystalline nature of the BTAB sample. The laser damage threshold (LDT) value of BTAB has been determined as 3.98 GW/cm2 from LDT analysis. The values of thermodynamic parameters like energy of activation, frequency factor, enthalpy change, entropy change and Gibbs free energy change have been calculated from Coats–Redfern model of thermal analysis. Computational studies have been carried out using the Density functional theory (DFT) and the values of hyper polarizability, dipole moment and polarizability of BTAB have been deduced. In order to comprehend the nature of charge distributions and donor–acceptor interactions prevailing in BTAB crystal, Natural bond analysis (NBO) has been carried out. The frontier orbital HOMO–LUMO approach has been employed to arrive at the values of the global chemical molecular reactivity descriptors.