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Slow Evaporation is the simplest way to grow crystals. The crystals of centrosymmetry glycine in its pure form show Second Harmonic Generation (SHG) upon occlusion of guest molecule. Non-Linear Optical (NLO) materials attained from amino acid have potential benefits in Second Harmonic Generation. Single crystal of glycine in the sight of small amount of Lithium Nitrate, Potassium Nitrate, Sodium Nitrate, Potassium Chloride, Potassium Bromide are good non-linear optical (NLO) materials. Crystals of glycine lithium nitrate have been grown by slow evaporation technique. Crystals of Glycine and Lithium Nitrate are grown by slow evaporation method and dopped with 20%, 30%, 50% and 60% of Sodium Nitrate and Potassium Nitrate. Sample surfaces and evaluation of the content ratio of doping material have been made by EDAX test, crystallinity and functional group of crystal characterized by FTIR studies, Band gap measured by UV method and morphology of crystals are studied by SEM analysis. [ABSTRACT FROM AUTHOR]

Transition metal alloys are valuable in material science research. In the present communication, Transition Metal Pseudopotential has been used to investigate lattice dynamics in symmetry and non-symmetry directions for binary alloy RhxAg1-x (x = 0.6, 0.8). In absence of any neutron scattering data and theoretical results, we present theoretical results which may be considered as a prediction. Further, we have studied temperature variation of Debye temperature (θD) and dynamical elastic constants (C11, C12 and C44). As experimental results are not available for elastic constants, we have compared our results with the values obtained by first principles method. Presently obtained results are comparable with such theoretical results. [ABSTRACT FROM AUTHOR]

An ab initio study of the temperature dependent elastic properties of CaO is carried out within the quasistatic approximation. Density functional theory (DFT) within the generalized gradient approximation (GGA) is used to carry out the computation. Elastic properties such as elastic constants (Cij), volume thermal expansion (β) and adiabatic and isothermal bulk moduli (BS and BT) are computed. In addition to that, we have also presented Young's modulus (Y), anisotropy factor (A), degree of elastic anisotropy (A*) and Poisson's ratio (v) upto 1200 K. A noticeable decrease in C11 and Y is observed compared to C12 and C44 as it approaches higher temperature. At higher temperatures, the elastic moduli gains linearity subject to softening due to thermal expansion. However, the obtained data are in good agreement with the experimental results. The thermal expansion (β) remains overestimated compared to the experimental data, which suggests insufficiency of quasistatic approximation at high temperatures to compute the mechanical properties. The adiabatic and isothermal bulk moduli are in reasonable agreement with the available findings. Increase is observed in A and A* with temperature while v decreases with temperature. However, rise is observed in v after 1000 K. The overestimated values of β is the main factor responsible for the discrepancy observed in the elastic properties, and the only way to overcome this discrepancy is to include anharmonic vibrational component of free energy, as the anharmonicity becomes dominant at higher temperatures and at melting. [ABSTRACT FROM AUTHOR]

We report analytical results for pair distribution function g(r) and structure factor S(q) for warm dense partially ionized aluminum plasma at metallic density employing a numerical scheme going beyond one component plasma (OCP) model. It is built on the effective charged hard sphere (e-CHS) based two-parameter model; packing fraction (η) and ion plasma parameter (Γ), but simplified to convert into a one-parameter scheme. Ion interaction through electron screening effect is determined within the linear response theory for dielectric function and a description beyond the random phase approximation (RPA) is incorporated through the local field correction. We employ a local pseudopotential comprises of a Hartree potential, exchange-correlation potential based on the local density approximation and a repulsive delta-function to achieve the orthogonalization effect of free electron states to the core states. Results for g(r) and S(q) are fitted to experimental and recent ab initio simulations findings to deduce effective charge in warm Al- plasma. We examine our scheme for temperature ranging from melting 0.08 eV up to 15 eV. Fitted parameters are compared and analyzed with quantum two component plasma (Q-TCP) model parameters. Good agreement with Q-TCP compared to OCP is discussed, which exemplifies the importance of proper account for exchange and correlation effect. The proposed scheme is further tested for some important thermodynamic quantities and results so deduced are validated with reported findings. Overall agreement for computed physical quantities confirms the need of screened electron-ion interaction and a scheme going beyond the OCP model for accurate determination for structure and thermodynamics of dense plasma. [ABSTRACT FROM AUTHOR]

Ca-based bulk metallic glasses (BMG) with their unique properties being very low density, good compressive strength and shear modulus comparable to modulus of human bones have found utility in biomedical field. Their poor oxidation and corrosion resistance can be improved substantially when they are synthesized in a glassy state. Although, according to the confusion principle, the bulk form of binary metallic system is seldom possible; recent experimental studies have aimed to achieve these goals and succeeded in preparing CaxAly binary BMG with (x, y) pair as (8, 3), (13,14) and (61, 39). We examine and verify the amorphous structure and glass forming temperature of binary Ca61Al39(at.%) metallic glass using molecular dynamics simulations combined with an evanescent form for interaction potential at the experimental density. Good agreement is observed with recent in-situ high energy X-ray experimental findings for pair-correlation function g(r) and static structure factor S(q). Evidenced from the structural analysis, the estimated liquid to glass transition temperature (Tg) is found between 520 to 555 K. Large principal peak heights in g(r) and S(q) is attributed to the strongness of the potential, whereas the large-r Friedel oscillations results in to the oscillatory behavior of g(r). Nevertheless, present result for co-ordination number (NC) 12.44 to 12.79 is in excellent agreement with the experimental value 11.9 ± 0.3 at Tg, and changes by about 7.6% when temperature is varied from 300 to 1200 K while keeping the density constant. Unlike the other composition pair (x, y) for Ca-based BMG, a large co-ordination number is suggestive, and proposes a closed packed structure in its probable solid phase. Since the closed packed structures are commonly observed with metallic materials, this proposition is partly supported by a successful application of the evanescent form for bare-ion local pseudopotential to analyze the structural aspect of binary Ca61Al39 metallic glass. [ABSTRACT FROM AUTHOR]

We report classical molecular dynamics (MD) simulation results for structural information of liquid Molybdenum at melting temperature. Effective interatomic interaction is deduced within the tight-binding second- moment approximation and extended up to three neighbor distance, as proposed by Karolewski [Radiation Effect & Defects in Solids, 153 (2001) 239]. By simultaneously varying density (ρ) and temperature (T), and observing the simulated system at a regular interval of time, we have estimated melting temperature (2903 K) and corresponding density (8.4915 g/cm3) is in agreement with the experimental and recent ab initio MD findings. Further, the pair-correlation function g(r) deduced at presently estimated melting temperature and density is analyzed in terms of coordination number and in reference to the assumed effective interaction potential. Unexpected large coordination number (12.84) found for such a BCC → liquid transition may be attributed to the limitation of the potential. Further, the Fourier transform of g(r) is used to derive static structure factor S(k) and its long wavelength limit is exploited to find compressibility. Relative position and nature of the first and the second peak in S(k) reveal following points: (i) first peak is symmetrical and (ii) the ratio of the position of the second peak to that of the first peak is 1.9013. This confirms that the system is fully melted into the normal liquid phase. [ABSTRACT FROM AUTHOR]