A.S. Haja Hameed

Studies on organic indole-3-aldehyde single crystals

Abstract Indole-3-aldehyde (IA) is a new organic nonlinear material for which its solubility in methanol and acetone was found out using the apparatus fabricated by the authors. In order to get the good-quality crystals, methods of evaporation of solvent at room temperature and slow cooling of saturated solution at boiling temperature were adopted. Simulated lattice parameter values were found out using experimentally known “ d ” values. The etching and mechanical strength studies on different planes of the crystal were carried out. Decomposition temperature, weight loss and different functional bond frequencies associated with the crystal were also found out from differential thermal analysis (DTA), thermo-gravimetric analysis (TGA) and Fourier transform infra-red (FTIR) spectroscopic analysis, respectively.

Synthesis, growth and characterization of nonlinear optical material: l-arginine fluoride

Abstract l -arginine fluoride (LAF) is one of the potential semi-organic materials for nonlinear optical applications. In the present study, synthesis, material purification and crystal growth of LAF have been carried out. Since the material has high solubility in water, the growth parameters have been optimized for the growth of good-quality crystals. X-ray powder diffraction studies have been carried out in order to calculate the lattice parameter values using its monoclinic crystallographic equation. From Fourier transform infrared spectroscopic analysis, different modes of vibration due to various functional groups present in LAF have been observed. In order to find the range and percentage of optical transmission, the UV–VIS spectrum was recorded for the crystal. The thermal behaviour of the LAF sample has been investigated from differential thermal and thermogravimetric analyses.

Inhibition of microbial growth, study of solution stability, growth and characterization of potassium fluoride mixed l-arginine phosphate single crystals

Abstract In order to alleviate the major problem of microbial growth and colouration in l -arginine phosphate (LAP), the use of potassium fluoride (KF), a new additive having higher dipole moment, has been proposed. The stabilities of the pure and KF mixed LAP solution at different temperatures have been determined. Pure and KF mixed LAP crystals were grown by the temperature lowering technique. The presence of potassium in the crystal was identified by inductively coupled plasma analysis (ICP). The lattice parameters for the grown crystals were determined from X-ray powder diffraction. The molecular vibration and thermal behaviour of KF mixed LAP were found from Fourier transform infrared (FTIR) spectroscopy and thermal analysis (DTA &TGA) respectively.

Nucleation kinetics, growth and characterization of dLAP, dLAP:KF and dLAP:NaN3 crystals

Abstract The nucleation parameters, such as interfacial tension, radius of the critical nucleus and critical free energy change have been estimated for deuterated l -arginine phosphate (dLAP), potassium fluoride mixed dLAP and sodium azide mixed dLAP single crystals. Pure and additive mixed dLAP single crystals are grown by slow cooling technique. The effect of microbial contamination and colouration on the growth solutions has been studied. The crystalline powder of the grown crystals has been examined by X-ray diffraction and thermal analyses in order to estimate the lattice parameters and study thermal properties respectively.

Effect of temperature and deuterium concentration on the growth of deuterated potassium dihydrogen phosphate (DKDP) single crystals

Abstract The growth condition of tetragonal phase deuterated potassium dihydrogen phosphate (DKDP) with higher deuterium concentration is optimized for the growth of large size crystals. The variation of lattice parameter values of the crystal in comparison with potassium dihydrogen phosphate (KDP) crystal is found. Etching studies have been done for both monoclinic and tetragonal phases of the DKDP crystals. The percentage and range of transmission of KDP and DKDP crystals were found from uv – visible spectroscopy.

Growth and optical characterization of organic nonlinear optical crystal: indole-3-aldehyde

Abstract The metastable zone width for the solution of organic nonlinear material: indole-3-aldehyde (IA) has been determined for the various solvents of acetone, methanol and ethyl acetate and the corresponding IA crystals have been grown by temperature lowering technique. The surface analysis on different planes of the grown crystals has been carried out. The range of transmission and powder second harmonic generation efficiency of IA have been reported.

Growth of stubbier habit LAP2 single crystals and their characterisation studies

Abstract One of the l -arginine salts, l -arginine diphosphate ( l -arg · 2H 3 PO 4 ) (LAP2) has been synthesised. The crystals of LAP2 are grown by slow evaporation technique and the habit of the crystal is explained. Etching studies have been done on the (100) and (011) faces of the grown crystals using water as an etchant. The lattice parameter values have been determined using X-ray powder diffraction analysis. The different modes of vibrations present in the crystal are identified from Fourier Infrared spectroscopy analysis. The melting point, decomposition temperature and weight loss during heating are found from the Differential Thermal (DT) and Thermogravimetric (TG) analyses. UV–VIS spectroscopy analysis has also been done on LAP2 crystal.

Growth and characterization of pure, chloroacetamide and 4-dimethylaminobenzaldehyde doped triglycine sulphophosphate (TGSP) crystals

Triglycine sulphophosphate (TGSP), chloroacetamide (AC) and 4-dimethylaminobenzaldehyde (DB) doped TGSP crystals were successfully grown from their respective aqueous solutions by slow cooling method. X-ray powder diffraction patterns were collected for pure, AC and DB doped TGSP crystals in order to determine their lattice parameter values. Fourier Transform Infra-Red (FTIR) spectroscopic analysis was carried out to confirm the molecular vibrations of TGSP and the presence of AC and DB in TGSP qualitatively. From the UV–Vis spectroscopic analysis, the absorption range was observed for the grown crystals. From the microhardness test, the Vickers’s hardness of the AC and DB doped TGSP crystals measured on (001) face was found to be higher than that of pure TGSP crystals. The dielectric studies showed the variation of dielectric constant as a function of frequency at room temperature. The thermal behavior of the pure and doped TGSP samples was studied from their thermogravimetric and differential thermal curves.

Optical amplification properties of a cyanine-dye-doped DNA-lipid complex fiber

A DNA-CTMA optical fiber was prepared by melt-spinning method for the first time. A hemicyanine dye, trans-4-(4-dibutylamino)-styryl)-1-methylpyridinium iodide (DBASMPI) doped DNA-CTMA fiber with core diameter of 1 mm and dye concentration of 3.6 wt% was obtained by soaking it in an aqueous dye solution. Laser (532 nm) pumped amplified spontaneous emission (ASE) at 610 nm was observed in the dye-doped DNA-CTMA fiber. The ASE occured at energy density 50 mW. The results from ASE emphasize that DBASMPI doped DNA-CTMA fiber is appealing as a good candidate for optical amplifiers and superfluorescence sources in a variety of communication and sensor applications.