Junaid, Bushiri M; Gopakumar, V; Vaidyan, V K(January 17, 2013)
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Abstract:
ZnO thin films were coated on amorphous glass substrate at various temperatures in the
range 160-500 0C by spray pyrolysis method. The as deposited films were characterised by
using XRD and SEM. Wurtzite phase of ZnO was formed at a substrate temperature of
400 0C, highly oriented (002) phase was developed with respect to increase of substrate
temperature from 450 to 500 0C. Morphological and growth mode of these films were
analyzed with respect to structural orientation of films from wurtzite to highly (002)
oriented phase. Present study reveals that substrate temperature was one of the important
parameters which determine the crystalline quality, population of defects, grain size,
orientation and morphology of the films
Description:
Journal of Optoelectronics and Biomedical Materials Vol. 5 Issue 1, January - March 2013 p. 1 - 8
Junaid, Bushiri M; Jayasree, R S; Annamma, John; Nayar, V U(Elsevier, July 27, 2005)
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Abstract:
Polarized Raman spectral changes with respect to temperature were investigated for Pr(BrO3)3·9H2O single crystals. FTIR spectra of
hydrated and deuterated analogues were also recorded and analysed. Temperature dependent Raman spectral variation have been explained
with the help of the thermograms recorded for the crystal. Factor group analysis could propose the appearance ofBrO3 ions at sites corresponding
to C3v (4) and D3h (2). Analysis of the vibrational bands at room temperature confirms a distorted C3v symmetry for the BrO3 ion in the crystal.
From the vibrations of water molecules, hydrogen bonds of varying strengths have also been identified in the crystal. The appearance υ1 mode
of BrO3− anion at lower wavenumber region is attributed to the attachment of hydrogen atoms to the BrO3− anion. At high temperatures,
structural rearrangement is taking place for bothH2Omolecule and BrO3 ions leading to the loss ofwater molecules and structural reorientation
of bromate ions causing phase transition of the crystal at the temperature of 447 K.
Junaid, Bushiri M; Mahadevan Pillai, V P; Pradeep, T; Jayasree, R S; Nayar, V U(Elsevier, 1997)
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Abstract:
FTIR and Raman spectra of FeClMoO4 single crystal and polycrystalline Na2MoO4, Na2MoO4·2H2O and
Na2MoO4·2D2O are recorded and analysed. The band positions for different modes suggest that MoO4 tetrahedron
is more distorted in FeClMoO4. The larger splitting observed for the bending modes and partial retention of
degeneracy of the asymmetric stretching mode indicate that angular distortion is greater than liner distortion in
MoO4 2 ion in FeClMoO4 confirming x-ray data. The non-appearance of the n1 and n2 modes in the IR and partial
retention of the degeneracies of various modes show that MoO4 2 ion retains Td symmetry in Na2MoO4. Wavenumber
values of the n1 mode indicate that the distortion of MoO4 tetrahedra in the four crystals are in the order
FeClMoO4\ Na2MoO4·2H2O\Na2MoO4·2D2O\Na2MoO4. The water bands suggest the presence of two
crystallographically distinct water molecules in Na2MoO4·2H2O. They form strong hydrogen bonds
Junaid, Bushiri M; Antony, C J; Michel, Fleck(Elsevier, May 27, 2007)
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Abstract:
The Raman and FTIR spectra of [C(NH2)3]2M(SO4)2 ·6H2O (withM= Co, Fe, Ni) were recorded and analysed. The observed spectral bands
are assigned in terms of vibrations of guanidinium ions, sulphate groups and water molecules. The analysis shows that the sulphate tetrahedra
are distorted from their free state symmetry Td to C1. This is attributed to the presence of hydrogen bonds from water molecules. The order of
distortion of the metal oxygen octahedra influenced the distortion of the sulphate tetrahedra. The appearance of 1– 3 modes of water molecules
above 3300 cm−1 indicates the presence of weak hydrogen bonds
Junaid, Bushiri M; Kochuthresia, T C; Athimoolam, S; Ramakrishnan, V; Vaidyan, V K(Scientific Research Publishing, January 10, 2013)
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Abstract:
Th(BrO3)3·H2O single crystals were grown from its aqueous solution at room temperature. Single crystal XRD, Raman and FTIR techniques were used to investigate the crystal structure. The crystal structure was solved by Patterson method. The as grown crystals are in monoclinic system with space group P21/c. The unit cell parameters are a = 12.8555(18) Å, b = 7.8970(11) Å, c = 9.0716(10) Å, = 90°, = 131.568° and = 90° and unit cell volume is 689.1(2) Å3. Z = 8, R factor is 5.9. The Raman and FTIR studies indicate the lowering of symmetry of bromate anion from C3V to C1. Hydrogen bonds with varying strengths are present in the crystal. The centrosymmetric space group P21/c of the crystal is confirmed by the non-coincidence of majority of Raman and IR bands
Description:
Crystal Structure Theory and Applications, 2013, 2, 70-74