Nmssvn College

Madurai, India

Nmssvn College

Madurai, India
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Amudhavalli A.,Nmssvn College | Rajeswarapalanichamy R.,Nmssvn College | Iyakutti K.,SRM University
Journal of Alloys and Compounds | Year: 2017

The search for stable half-metallic ferromagnetic materials remains a high priority in condensed matter Physics. Ab initio calculations are performed using density functional theory to analyze the structural phase stability, electronic structure, mechanical and magnetic properties of Mn based half Heusler alloys XYZ (X = Ir, Pt, Au; Y = Mn; Z = Sn, Sb) for three different phases namely α, β and γ phases of C1b crystal structure. This work aims to identify the ferromagnetic and half-metallic behavior of XYZ (X = Ir, Pt, Au; Y = Mn; Z = Sn, Sb) half Heusler alloys. To accomplish this, density functional theory (DFT) with generalized gradient approximation formulated by Perdew, Burke and Ernzerhof (GGA-PBE) and the Hubbard formalism (GGA-PBE + U) are used to describe the strong correlations present in these alloys. Among the considered phases, α-phase is found to be the lowest energy phase for IrMnSn, IrMnSb, PtMnSn, PtMnSb, AuMnSn and AuMnSb at normal pressure. A pressure-induced structural phase transition is observed in IrMnSn, IrMnSb, PtMnSn, PtMnSb, AuMnSn and AuMnSb at the pressures of 62.1 GPa, 47.8 GPa, 26.1 GPa, 25.3 GPa, 23.7 GPa and 14.0 GPa respectively. The electronic structure reveals that these materials are metals at normal pressure whereas half metals at high pressure. The magnetic moments for these half Heusler alloys in all the three different phases (α, β and γ) are estimated. © 2017 Elsevier B.V.

Vanitha Kumari G.,Arul Anandar College | Ananth N.,Zhejiang University | Asha,Arul Anandar College | Mathavan T.,Nmssvn College | Jothi Rajan M.A.,Arul Anandar College
Materials Today: Proceedings | Year: 2016

Bimetallic Silver/Gold nanoparticles were prepared through chemical reduction in aqueous solution, following a method that was affable to the environment, allowing us to use this for medical purposes. AgNO3 and HAuCl4 were reduced using in-situ techniques in the presence of pectin and folic acid. Using the optical properties of metallic nanoparticles, surface plasmon resonance of metal nanoparticles was determined by UV-Vis spectroscopy, and the values acquired for silver and gold were found to be approximately 350 nm and 530 nm in wavelength respectively. The absorption peaks of the surface plasmon band shows a shift due to the size of the nanoparticles. The average hydrodynamic diameter and the size distribution of the synthesized nanoparticles achieved from dynamic light scattering technique. The folic acid conjugated Ag nanoparticles morphology are gathered by scanning electron microscopy (SEM), functional group by Fourier transform infrared (FTIR) spectroscopy respectively. The development of this process, which is gentle for the environment, opens the possibility for numerous applications in the areas of biomedical applications. © 2016 Elsevier Ltd.

Premkumar S.,Nmssvn College | Rekha T.N.,Lady Doak College | Mohamed Asath R.,Nmssvn College | Mathavan T.,Nmssvn College | Milton Franklin Benial A.,Nmssvn College
European Journal of Pharmaceutical Sciences | Year: 2016

Conformational and molecular docking analysis of 2-acetylamino-5-bromo-6-methylpyridine molecule was carried out and the vibrational spectral analysis was also carried out using experimental and theoretical methods. The calculated and experimentally observed vibrational frequencies of the molecule were assigned and compared. The pyridine ring CH stretching and CH3 stretching vibrational modes were shifted towards higher wavenumber (blue shift). The C=O stretching vibrational frequency was shifted towards lower wavenumber (red shift). Ultraviolet-visible spectrum of the molecule simulated theoretically was further validated experimentally. Molecular reactivity and stability were investigated using the frontier molecular orbital analysis and the related quantum chemical molecular properties. Natural bond orbital analysis and the structure activity relations were also studied to confirm the bioactivity of the molecule. Anticancer activity was examined based on molecular docking analysis and it has been identified that the AABMP molecule can act as a good inhibitor against lung cancer. © 2015 Elsevier B.V.

Parameswari A.,Nmssvn College | Milton Franklin Benial A.,Nmssvn College
AIP Conference Proceedings | Year: 2016

Surface enhanced Raman scattering (SERS) studies of glycine (Gly) adsorbed on silver nanoparticles (AgNPs) was investigated by experimental and density functional theory approach. The AgNPs were prepared and characterized. The molecular structure of the Gly and Gly adsorbed on silver cluster were optimized by the DFT/B3PW91 method with LanL2DZ basis set. The calculated and observed vibrational frequencies were assigned on the basis of potential energy distribution calculation. The perpendicular orientation of Gly on the silver surface was predicted from the enhanced Raman signal correspond to the C=O and C-H stretching vibrational modes. The frontier molecular orbitals analysis and molecular electrostatic potential calculation were carried out. The reduced band gap value was obtained for Gly adsorbed on silver nanoparticles, which paves the way for designing the bio molecular devices. The first order hyperpolarizability value for Ag-Gly is 461 times greater than the urea. Thus, Ag-Gly is a promising candidate for NLO materials. © 2016 Author(s).

Amudhavalli A.,Nmssvn College | Rajeswarapalanichamy R.,Nmssvn College
AIP Conference Proceedings | Year: 2016

Ab initio calculations are performed to investigate the structural stability, electronic structure, mechanical properties and optical properties of half Heusler alloys (LiBeAs and LiBeSb) for three different phases of zinc blende crystal structure. Among the considered phases, α- phase is found to be the most stable phase for these alloys at normal pressure. A pressure induced structural phase transition from α-phase to β- phase is observed for LiBeAs. The electronic structure reveals that these alloys are semiconductors. The optical properties confirm that these alloys are semiconductor in nature. © 2016 Author(s).

Asvini Meenaatci A.T.,Nmssvn College | Rajeswarapalanichamy R.,Nmssvn College | Iyakutti K.,SRM University
Solid State Sciences | Year: 2013

The electronic, structural, mechanical and superconducting properties of group VB mononitrides are investigated by means of first principles calculation based on density functional theory with generalized gradient approximation. The calculated ground state properties are in good agreement with previous experimental and theoretical results. Among the three crystallographic structures that have been investigated, the hexagonal WC phase is found to more stable than the cubic ones. Under high pressure, a series of structural phase transition from WC → NaCl → CsCl phase is also predicted in VN, NbN and TaN. The calculated elastic constants indicate that all the three nitrides are mechanically stable at ambient pressure. The estimated Zener ratio and linear compressibility coefficients Kc/Ka reveals that these materials exhibit elastic anisotropy. The estimated superconducting transition temperature (Tc) values as a function of pressure for VN, NbN and TaN are 35.5, 37.5 and 30.5 K respectively. © 2013 Elsevier Masson SAS. All rights reserved.

Mangaiyarkkarasi J.,NMSSVN College | Saravanan R.,The Madura College
Journal of Materials Science: Materials in Electronics | Year: 2016

In this work, we report the influences of Ce doping on structural, morphological, optical and charge derived properties of BaTi1−xCexO3 (x = 0.02, 0.04, 0.06 & 0.08) ceramic synthesized by high temperature solid state reaction method. This ceramic has been characterized by powder X-ray diffraction (PXRD), UV–visible spectrometry, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Lattice parameters were determined through the profile refinement technique using PXRD data. Charge density redistribution and bonding nature of the grown systems are analyzed by maximum entropy method (MEM). Incorporation of rare earth ion Ce into the BaTiO3 lattice enhances the ionic nature between Ba and O ions and decreases the ionic nature between Ti and O ions, revealed from the qualitative and quantitative analysis by MEM. Optical band gap values are estimated for the prepared samples from UV–Vis data. Formation of aggregated particles with low porosity is observed from SEM micrographs. The chemical compositions of the prepared samples are further confirmed by EDS spectral analysis. © 2016 Springer Science+Business Media New York

Saravanan R.,The Madura College | Mangaiyarkkarasi J.,NMSSVN College
Journal of Materials Science: Materials in Electronics | Year: 2016

The Ba1−xSrxTiO3 perovskites (abbreviated as BST, x = 0.2, 0.4 and 0.6) have been synthesized by high temperature solid state reaction technique. The influences of Sr doping on the morphology, electron density distribution and optical properties at the lattice sites of BaTiO3 have been investigated by X-ray diffraction, scanning electron microscopy and UV–visible spectroscopy. With the increase in Sr content, the lattice parameter, cell volume, density and the grain sizes are found to be reduced. The incorporation of Sr content into the BaTiO3 lattice decreases the ionic nature of the bonding between Ti and O ions and increases ionic nature between Ba and O ions and the energy gap measurements indicate the reduction in insulating property of the grown samples. The stoichiometry of the samples was further confirmed by energy dispersive X-ray spectroscopy. © 2015, Springer Science+Business Media New York.

Malathy P.,Nmssvn College | Vignesh K.,P.A. College | Rajarajan M.,P.A. College | Suganthi A.,P.A. College
Ceramics International | Year: 2014

Transition metal (M=Ni and Zn) doped Bi2O3 nanoparticles were prepared by the precipitation method to enhance the photocatalytic activity of Bi2O3. The as-prepared nanoparticles were characterized by different techniques such as powder-X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (UV-vis-DRS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and photoluminescence (PL) techniques. The photocatalytic activity was evaluated by the degradation of malachite green (MG) dye under visible light irradiation. The results revealed that Ni doped Bi2O3 (Ni-Bi 2O3) exhibited higher photocatalytic activity when compared to that of other photocatalysts. A set of optimized conditions such as pH, catalyst concentration and initial dye concentration on the photodegradation of MG were investigated in detail. © 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.

Benial A.M.F.,NMSSVN College | Dhas M.K.,NMSSVN College | Jawahar A.,NMSSVN College
Applied Magnetic Resonance | Year: 2011

The mobility studies on 14N-labeled TEMPONE, TEMPO, carbamoyl-PROXYL, carboxy-PROXYL in high viscous liquid were carried out on a 300 MHz electron spin resonance (ESR) spectrometer. The ESR parameters, such as a line width, signal intensity ratio, g-factor, hyperfine coupling constant and correlation time, were determined. The line width broadening increases twofold in high viscous samples of 14N-labeled carbamoyl-PROXYL and carboxy-PROXYL, but this line broadening is negligibly small in the high viscous sample (85% glycerol) of 14N-labeled TEMPO. The correlation time also increases (~30 times) in the high viscous sample (85% glycerol) of 14N-labeled carbamoyl-PROXYL and carboxy-PROXYL, but there is no considerable increase in the high viscous sample of 14N-labeled TEMPO. TEMPONE has the narrowest line width and is also highly sensitive to viscosity. The correlation time increases (~13 times) in the high viscous sample (85% glycerol) of 14N-labeled TEMPONE. Therefore, this study reveals that the 14N-labeled TEMPONE radical is the most suitable spin probe for in vivo studies in high viscous biological fluids. © 2011 Springer-Verlag.

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