Pd(II)-doping studies on tris(thiourea)zinc(II) sulphate crystals: Catalytic effect of Pd(II)-doping on SHG efficiency

Single crystals of Pd(II)-doped tris(thiourea)zinc(II) sulphate (ZTS) have been grown from an aqueous solution by conventional slow evaporation solution growth technique. The characteristic functional groups have been identified by FTIR analysis. Crystal stress has been indicated by powder XRD patterns and FTIR analysis. Incorporation of dopant into the crystalline matrix during crystallization process has been evidenced by energy dispersive X-ray spectroscopy and quantified by inductively coupled plasma technique. The surface morphological changes have been observed in the doped specimen. Mechanical stability of the as-grown specimen has been analyzed by Vickers microhardness analysis. Thermal studies reveal no decomposition up to the melting point. Lattice parameters determined by single crystal XRD analysis reveal only minor variations as a result of low doping. Pd(II) doping has a catalytic effect on the second harmonic generation efficiency improvement of zinc thiourea complex

Effect of doping cations Li(I)-, Ca(II)-, Ce(IV)- and V(V)- on the properties and crystalline perfection of potassium dihydrogen phosphate crystals: A comparative study

The effect of doping metal ions with varied ionic charges (ranging from +1 to +5), Li(I)-, Ca(II)-, Ce(IV)- and V(V)- on the growth process and properties of potassium dihydrogen phosphate (KDP) crystals, grown by slow evaporation solution growth technique, has been investigated. Incorporation of metal ion into the KDP crystalline matrix is well confirmed by energy dispersive X-ray spectroscopy and atomic absorption spectroscopy. Interesting to observe that the incorporation is comparatively less in doping the higher valent metal. The powder XRD pattern and Fourier transform-IR analysis confirm the slight distortion in the structure of the KDP crystals as a result of metal ion doping. Slight changes in cell parameter values of doped KDP crystals are observed by single crystal XRD analysis. The high-resolution X-ray diffraction (HRXRD) studies used to evaluate the crystalline perfection reveal many interesting features on the ability of accommodating the dopants by the crystalline matrix. Surface morphological changes because of foreign metal ion incorporation are observed by scanning electron microscopy. UV-Vis spectroscopy reveals that the transparency is not affected much by the dopants and the cut-off wavelengths of all the doped specimens lie in a close range. Band-gap energies are estimated using optical transmittance data. Enhanced second harmonic generation efficiency is observed

Co(II), Co(II) plus Mn(II), Co(II) plus Ni(II) Co-doping Effects on Tris(thiourea)zinc(II) Sulphate Crystals: A Comparative Study

The influence of Co(II), Co(II)+Mn(II), Co(II)+Ni(II) co-doping on the structure and crystalline perfection of tris(thiourea)zinc(II) sulphate single crystals grown from an aqueous solution at room temperature by slow evaporation solution growth technique has been investigated. The incorporation of foreign metal into the crystalline lattice was well confirmed by chemical formula determined by single-crystal X-ray diffraction analysis. The intensity variations observed in powder X-ray diffraction patterns and slight shifts in vibrational frequencies in Fourier transform IR indicate the lattice stress. Thermal studies reveal the purity of the material and no decomposition is observed up to the melting point. High-resolution X-ray diffraction studies reveal that Co(II)-doped specimen has no clustering of defects while the Co(II)+Mn(II), Co(II)+Ni(II) co-doped crystals show the presence of structural grain boundaries as a result of crystal stress and strain. The as-grown crystals are further characterized by Kurtz powder technique and dielectric studies. Good transparency in the visible region is observed for all the specimens. Interestingly, in co-doping the host crystal selectively accommodates only one foreign metal ion as revealed by single-crystal XRD analysis

Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy

Transparent optical quality single crystals of imidazolium L-tartrate (IMLT) were grown by conventional slow evaporation solution growth technique. Crystal structure of the as-grown IMLT was determined by single crystal X-ray diffraction analysis. Thermal analysis reveals the purity of the crystal and the sample is stable up to the melting point. Good transmittance in the visible region is observed and the band gap energy is estimated using diffuse reflectance data by the application of Kubelka-Munk algorithm. The powder X-ray diffraction study reveals the crystallinity of the as-grown crystal and it is compared with that of the experimental one. An additional peak in high resolution X-ray diffraction (HRXRD) indicates the presence of an internal structural low angle boundary. Second harmonic generation (SHG) activity of IMLT is significant as estimated by Kurtz and Perry powder technique. HOMO-LUMO energies and first-order molecular hyperpolarizability of IMLT have been evaluated using density functional theory (DFT) employing B3LYP functional and 6-31G(d,p) basis set. The optimized geometry closely resembles the ORTEP. The vibrational patterns present in the molecule are confirmed by FT-IR coinciding with theoretical patterns