Vol 26 No 5-7

Asian Journal of Physics Vol. 26 No 5-7 (2017) 221-235

Nonlinear optical properties with spectral analysis of DL-Valinium nitrate- a DFT approach

G Edwin Sheelaa,C, D Manimaranb, I Hubert Joeb*,and V Bena JothyC
^aDepartment of Physics, Muslim Arts College, Thiruvithancode-629 174, India
^bCentre for Molecular and Biophysics Research, Department of Physics, Mar Ivanios College, Thiruvananthapuram-695 015, India
^cDepartment of Physics, Women’s Christian College, Nagercoil-629 001, India

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An organic nonlinear optical (NLO) single crystal was synthesized by slow solvent evaporation technique from aqueous solutions of DL-valine and nitric acid (DLVN) at ambient temperature. The powder X-ray diffraction of the grown crystal was recorded and indexed. The optimized molecular structure, vibrational wavenumbers have been calculated by using density functional method (B3LYP) with the standard 6-311++G (d,p) basis set.. The normal coordinate analysis has been performed for a systematic assignment of IR and Raman bands with percentage PED. The strong hyperconjugative interaction and charge delocalization that leads to the stability of the molecule have been investigated with the aid of natural bond orbital (NBO) analysis. The frontier molecular orbital were constructed and the HOMO and LUMO energies were measured. The optical absorption study reveals the transparency of the crystal in the entire visible region and the lower edge was found to be 298 nm. Relative powder second harmonic generation (SHG) efficiency of the grown crystal was tested by Kurtz and Perry powder technique. © Anita Publications. All rights reserved.
Keywords: NLO, FT-IR, FT-Raman, NBO

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Asian Journal of Physics Vol. 26 No 5-7, (2017) 237-248

Structural and biological studies of 3-formyl-4-methoxyphenylboronic acid:
density functional theory and molecular docking approach

D Manimarana, I Hubert Joe^a,*, Sunila Abrahamb
^aCentre for Molecular and Biophysics Research, Department of Physics, Mar Ivanios College, Thiruvananthapuram-695 015, Kerala, India
^bDepartment of Physics, Christian College, Chengannur-689 122, Kerala, India

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Optimized geometry, hydrogen bonding interactions and biological evaluation of 3-formyl-4-methoxyphenylboronic acid have been investigated using vibrational spectroscopy techniques and molecular docking. Blue-shifting of C-H...O and red-shifting of O-H...O stretching wavenumbers confirm the presence of inter- and intra-molecular hydrogen bonding. The vibrational mode assignment has been performed on the basis of potential energy distribution by scaled quantum mechanical force-field methodology. The structural conformations of the molecule have been analyzed based on the molecular orbital calculations. The biological activity of the molecule has been evaluated with aurora-a kinease inhibited target protein. © Anita Publications. All rights reserved.
Keywords: Boronic acid; DFT; Molecular docking; FTIR; FT-Raman

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Asian Journal of Physics Vol. 26 No 5-7, (2017) 249-261

Structural and spectral studies of non-linear crystal L-Phenylalaninium Maleate

D R Leenaraj and I. Hubert Joe*
Centre for Molecular and Biophysics research, Department of Physics,
Mar Ivanios College, Thiruvananthapuram-695 015, India.
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The single crystals of L-Phenylalaninium maleate are grown by slow evaporation technique and Fourier transform infrared and Raman spectra of the crystal was recorded and analyzed. The geometry, intermolecular hydrogen bonding and harmonic vibrational wavenumbers were calculated with the help of density functional theory method. A detailed interpretation of the vibrational spectra was carried out with the aid of potential energy distribution analysis. Vibrational analysis reveals the presence of O–H…O and N–H…O hydrogen bonding in the crystal. Theoretically predicted first order hyperpolarizability and HOMO─LUMO energy gap exhibits the non-linear optical activity. © Anita Publications. All rights reserved.

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Asian Journal of Physics Vol. 26, No 5-7 (2017) 263-269

Study of synthesis and characterization of iron oxide (Fe₃O₄) nanoparticles using PVP as stabilizers

S Veena Gopal and I Hubert Joe*
Centre for Molecular and Biophysics research, Department of Physics, Mar Ivanios College,
Thiruvananthapuram-695 015, India.

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Presenting one step process for the synthesis of iron Oxide nanoparticles, aqueous colloid using the multifunctional Poly Vinyl Pyrollidone (PVP), which electro statically complexes with aqueous Iron ions (One precursor as Fe2+ from FeCl2), reduces them and subsequently caps the nanoparticles [1]. The aqueous magnetic nano crystalline colloids centrifuged and filtered. The prepared samples were characterized by electronic spectra. Powdered XRD measurement shows that the peak of the diffractogram is in well agreement with theoretical data of Fe3O4. The crystalline size of the particles ranges from7-16nm with the increasing concentration of Poly Vinyl Pyrollidone (PVP). SEM studies shows that the agglomeration of the particle is found sensitive to PVP concentration. By the addition of PVP as a stabilizer, the particle was found separated which find application in MRI contrast agent. © Anita Publications. All rights reserved.
Keywords: Boronic acid; DFT; Molecular docking; FTIR; FT-Raman

Total Refs : 9

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Intervention Journal,2010,6(2).
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Asian Journal of Physics Vol. 26, No 5-7 (2017) 271-282

Space weather and ionospheric variability over low latitudes

Kamsali Nagaraja, B Praveen Kumar and S C Chakravarty
Department of Physics, Bangalore University, Bengaluru -560 056, India
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A real-time model has been used to generate grid based Vertical Total Electron Content (VTEC) maps using ground based observation data from a network of dual frequency GPS (Global Positioning System) receivers deployed over the Indian region under the GAGAN (GPS Aided Geo Augmented Navigation) project. The output of a 24-hour model run of all stations includes hourly average values and diurnal plots of VTEC with 1° × 1° resolution in latitude-longitude. Apart from its utility for the navigation purpose, this real-time model is potentially suited to study ionosphere variations at high temporal and spatial resolutions. Using the available multi-station data for the low solar activity period of May 2007 to April 2008, the real-time model outputs are further analyzed to obtain monthly average diurnal variations grouped into equatorial (11-18° N) and anomaly (19-24° N) latitude zones. These monthly average diurnal curves are also produced using the IRI model under similar conditions. A comparison between the present real-time model and IRI model results for the winter, summer and equinoctial months show reasonably good agreement in overall magnitudes but there are some differences in the overall shape of the diurnal curve which appears much simplified for IRI model. The day to day and latitudinal variability of the VTEC are studied to understand the base level dynamics of the system. This is required if the VTEC data is to be used to search for signals pertaining to the space weather and geophysical phenomena. © Anita Publications. All rights reserved.
Keywords: TEC, GAGAN,Space weather ,Vertical Total Electron Content (VTEC), GPS (Global Positioning System) , Equinoctial months

Total Refs : 13

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10(2012)S08009; doi:10.1029/2012SW000780
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industrial electrical equipment, Space Weather, 12(2014)487-498, doi:10.1002/2014SW001066, 2014
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