Sciencia Acta Xaveriana

11 - 26

Authors: D. Prem Anand, P. Christuraj, M. Lalitha, S. Anbarasu, P.S. Joseph, A. Jestin Lenus, T. Kishore Kumar

Single crystal of semi organic nonlinear optical (NLO) material Copper Guanidinium Sulphate (CGS) of dimension 15X10X10 mm3 was grown by slow evaporation growth technique at room temperature. Single crystal X-ray diffractometer was utilized to measure the unit cell parameters and to confirm the crystal structure. The structure of the compound was confirmed by FTIR spectral analysis. The UV-Vis-NIR result shows that the crystal has a sharp cut-off at 330 nm and is nearly 75% transparent over a wide wavelength range enabling it for optoelectronics application. The optical energy gap of CGAS was found to be 4.86 eV. The microhardness data suggest that CGS belongs to a hard material category. The various mechanical properties fracture, toughness, brittleness context and stiffness constant were evaluated. Thermal properties of CGS crystal was investigated using TG/DTR analyses, which reveals that the material does not decomposed before melting. The resistivity and conductivity of the CGS crystal were found to be 6800 nm and 1.47 X 10-4 sm-1 respectively. The dielectric response of the sample has been studied in the frequency range 1 KHz – 10 MHz at room temperature. Kurtz powder technique confirms the second harmonic signal generation in the sample.

45 - 60

Authors: P. Sagayaraj, R. Gunaseelan, S. Selvakumar

An organic single crystal 4-N,N-dimethylamino-4’-N’-methylstilbazolium iodide (DMSI) which has high third order optical nonlinearity was successfully grown by slow solvent evaporation technique at room temperature. The grown single crystal was subjected to different characterization analyses to find out its suitability for device fabrication. The single crystal X-ray diffraction (XRD) and powder XRD analyses confirmed the crystal structure. This compound was characterized by functional groups analyses using CHN and proton NMR spectrum. It is evident from the optical absorption study that the crystal has excellent transmission in the entire visible region with its lower cut off wavelength is around 572 nm. The thermal stability of the compound was determined by thermal analyses of the specimen. The electrical properties of the crystal are investigated by ac, dc and photoconductivity measurements.

67 - 72

Authors: Prem Anand Devarajan, J. Jori Bindhu, S. Anbarasu, K. Kaviyarasu, T. Kishore Kumar

We report here the growth of sulphamic acid NLO single crystals by slow evaporation technique. Sulphamic acid single crystals of dimension 10×12×10 mm3 were harvested in a period of a month. The as grown sulphamic acid NLO single crystals were characterized by XRPD, FTIR, UV-vis-NIR spectral analyses and dielectric studies. The second harmonic generation was confirmed by Kurtz - Perry powder test.

79 - 86

Authors: Prem Anand Devarajan, B Surya, S Anbarasu, K Kaviyarasu, T Kishore Kumar

Optically good quality single crystals of organic non-linear optical 4- nitrophenol doped benzoyl glycine (4NPBG) were grown by slow evaporation technique. The grown crystals were characterized by Powder XRD, FTIR, UVvis- NIR spectral analysis and Kurtz-Perry powder test.

107 - 114

Authors: A Lourdusamy, C Muthulakshmi

The generalized pebbling number of a graph G, fgl(G), is the least positive integer n such that however n pebbles are placed on the vertices of G, we can move a pebble to any vertex by a sequence of moves, each move taking p pebbles off one vertex and placing one on an adjacent vertex. In this paper, we determine the generalized pebbling number of wheel Wn, fan Fn and complete r-partite graph.