Vyasa Upadhyaya | Manipal Academy of Higher Education (original) (raw)
Papers by Vyasa Upadhyaya
Physica B: Condensed Matter
Journal of Molecular Structure
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
Boric oxide based quaternary glasses in the system PbF2-TeO2-B2O3-Eu2O3 have been prepared by mel... more Boric oxide based quaternary glasses in the system PbF2-TeO2-B2O3-Eu2O3 have been prepared by melt quenching technique. Density, molar volume, FTIR, UV-Vis techniques were used to probe the structural modifications with incorporation of europium ions in the glass network. An increase in glass density & decrease in molar volume (Vm) values proved the structural changes occurring in coordination of boron atom [conversion of BO3 units to BO4]. This resulted in the increase of the compaction of the prepared glasses with increase in Eu2O3 contents. The amorphous natures of the samples were ascertained by XRD and metallization criterion (M) studies. XPS study showed the values of core-level binding energy [O1s, Eu3d, Eu4d, Te3d, Te4d, Pd4f, Pb5d, O1s, and F1s] of (PbF2-TeO2-B2O3-Eu2O3) the glass matrix. The frequency and temperature dependence of dielectric properties of present glasses were investigated in the frequency range of 1 Hz-10 MHz and temperature range of 313-773K. The study of dielectric measurements proved good insulating and thermal stability of the prepared glasses. At room temperature, dielectric loss [tanδ] values were negligibly small for prepared glasses and increased with increase in temperature. FTIR spectroscopy results were in good agreement with optical band energy gap, density, molar volume and hardness values revealing network modifications caused by europium ions in the glass structure.
Molecular Crystals and Liquid Crystals, 2015
Journal of Optics, 2012
ABSTRACT The nonlinear optical single crystals like L-alanine cadmium chloride (LACC), L-alanine ... more ABSTRACT The nonlinear optical single crystals like L-alanine cadmium chloride (LACC), L-alanine doped potassium dihydrogen orthophosphate (KDP) and L-arginine doped KDP were grown by slow evaporation method at room temperature. The grown crystals were exposed to Co-60 gamma radiation in the total doses ranging from 100 krad to 6 Mrad. The structural properties, change in absorption spectra, refractive index (RI) and second harmonic generation (SHG) performance of these crystals were investigated before and after irradiation. An X-ray diffraction studies reveal that the compressive strains are generated in the irradiated crystals. The ultraviolet - visible spectra show that the optical absorption increases with increase in radiation dose in the case of LACC crystal. There is no systematic behaviour in the optical absorption of L-alanine and L-arginine doped KDP crystals with increase in the radiation dose. A considerable change in the values of RI was observed due to irradiation. The SHG efficiency of LACC crystals were found to decrease with increase in radiation dose where as in case of L-alanine doped KDP crystals, the SHG efficiency was found to increase with increase in radiation dose.
Chemical Science Transactions, 2014
A chalcone derivative, 1-(5-bromothiophen-2-yl)-3-(2,3-dimethoxyphenyl)prop-2-en-1one (BTDMP), ha... more A chalcone derivative, 1-(5-bromothiophen-2-yl)-3-(2,3-dimethoxyphenyl)prop-2-en-1one (BTDMP), has been synthesized and grown as a high-quality single crystal by the slow evaporation solution growth technique. The compound was characterized by FT-IR and NMR studies. The crystal has been subjected to single-crystal x-ray diffraction studies and cell parameters of the crystal were determined. The title compound crystallizes in monoclinic system with a centrosymmetric space group P21/c, with unit cell parameters a= 11.6473(6) Å, b= 8.5651(5) Å, c= 14.4829(8) Å, α= 90 ο , β= 99.853(2) ο , γ = 90 ο and V= 1423.51(14) Å 3. The thermal stability of the crystal was determined from DSC curve. The grown crystals were characterized for their optical transmission and mechanical hardness. The potential of these crystals for NLO applications were studied using molecular hyperpolarizability calculations using MOPAC 2012.
AIP Conference Proceedings, 2011
A potentially useful nonlinear optical (NLO) organic material, 1-(5-chlorothiophen-2-yl)-3-(24,5-... more A potentially useful nonlinear optical (NLO) organic material, 1-(5-chlorothiophen-2-yl)-3-(24,5-trimethoxyphenyl)prop-2-en-1-one(CTTMP), has been synthesized and grown as a high-quality single crystal by the slow evaporation technique. The grown crystals were characterized by UV-visible spectroscopy. The material has thermal stability up to its melting point. Single beam Z-scan technique was employed to study the third order NLO properties of the material.
Journal of Molecular Structure, 2013
ABSTRACT A new potentially useful nonlinear optical (NLO) organic material, 1-(5-bromothiophen-2-... more ABSTRACT A new potentially useful nonlinear optical (NLO) organic material, 1-(5-bromothiophen-2-yl)-3-(4-nitrophenyl)prop-2-en-1-one (BTNP), has been synthesized and grown as a high-quality single crystal by the slow evaporation technique. The grown crystals were chemically characterized by FT-IR and NMR studies. The grown crystal has been subjected to single-crystal X-ray diffraction studies and cell parameters of the crystal were determined. The title compound crystallizes in triclinic system with a noncentrosymmetric space group P1, with unit cell parameters a = 4.8093(4) Å, b = 5.9428(6) Å, c = 11.5153(11) Å, α = 94.999(4), β = 95.780(3), γ = 96.396(4) and V = 323.79(5) Å3. The thermal stability of the crystal was determined from DSC curve. The grown crystals were characterized for their optical transmission and mechanical hardness. The second harmonic generation (SHG) efficiency of the crystals was obtained by powder technique using Nd:YAG laser and is found to be four times that of urea.
Journal of Crystal Growth, 1998
Acta Crystallographica Section E Structure Reports Online, 2012
Acta Crystallographica Section E Structure Reports Online, 2011
Acta Crystallographica Section E Structure Reports Online, 2002
ABSTRACT The title compound, C8H6Cl3NO, also known as N-(2,4,5-trichlorophenyl)acetamide, is an o... more ABSTRACT The title compound, C8H6Cl3NO, also known as N-(2,4,5-trichlorophenyl)acetamide, is an organic non-linear optical material. It crystallizes in the monoclinic system, in the non-centrosymmetric space group Pn.
Acta Crystallographica Section E Structure Reports Online, 2002
ABSTRACT The title compound, C11H15NO, also known as N-(2,4,6-trimethylphenyl)acetamide, is a... more ABSTRACT The title compound, C11H15NO, also known as N-(2,4,6-trimethylphenyl)acetamide, is an organic non-linear optical material. It crystallizes in the monoclinic system, in a non-centrosymmetric space group Pn.
Acta Crystallographica Section E Structure Reports Online, 2002
ABSTRACT The title compound, also known as N-(3-nitrophenyl)acetamide, C8H8N2O3, is an organic... more ABSTRACT The title compound, also known as N-(3-nitrophenyl)acetamide, C8H8N2O3, is an organic non-linear optical material. It crystallizes in the monoclinic system in the chiral space group P21, and there are four independent molecules in the asymmetric unit.
Acta Crystallographica Section E Structure Reports Online, 2011
Physica B: Condensed Matter
Journal of Molecular Structure
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
Boric oxide based quaternary glasses in the system PbF2-TeO2-B2O3-Eu2O3 have been prepared by mel... more Boric oxide based quaternary glasses in the system PbF2-TeO2-B2O3-Eu2O3 have been prepared by melt quenching technique. Density, molar volume, FTIR, UV-Vis techniques were used to probe the structural modifications with incorporation of europium ions in the glass network. An increase in glass density & decrease in molar volume (Vm) values proved the structural changes occurring in coordination of boron atom [conversion of BO3 units to BO4]. This resulted in the increase of the compaction of the prepared glasses with increase in Eu2O3 contents. The amorphous natures of the samples were ascertained by XRD and metallization criterion (M) studies. XPS study showed the values of core-level binding energy [O1s, Eu3d, Eu4d, Te3d, Te4d, Pd4f, Pb5d, O1s, and F1s] of (PbF2-TeO2-B2O3-Eu2O3) the glass matrix. The frequency and temperature dependence of dielectric properties of present glasses were investigated in the frequency range of 1 Hz-10 MHz and temperature range of 313-773K. The study of dielectric measurements proved good insulating and thermal stability of the prepared glasses. At room temperature, dielectric loss [tanδ] values were negligibly small for prepared glasses and increased with increase in temperature. FTIR spectroscopy results were in good agreement with optical band energy gap, density, molar volume and hardness values revealing network modifications caused by europium ions in the glass structure.
Molecular Crystals and Liquid Crystals, 2015
Journal of Optics, 2012
ABSTRACT The nonlinear optical single crystals like L-alanine cadmium chloride (LACC), L-alanine ... more ABSTRACT The nonlinear optical single crystals like L-alanine cadmium chloride (LACC), L-alanine doped potassium dihydrogen orthophosphate (KDP) and L-arginine doped KDP were grown by slow evaporation method at room temperature. The grown crystals were exposed to Co-60 gamma radiation in the total doses ranging from 100 krad to 6 Mrad. The structural properties, change in absorption spectra, refractive index (RI) and second harmonic generation (SHG) performance of these crystals were investigated before and after irradiation. An X-ray diffraction studies reveal that the compressive strains are generated in the irradiated crystals. The ultraviolet - visible spectra show that the optical absorption increases with increase in radiation dose in the case of LACC crystal. There is no systematic behaviour in the optical absorption of L-alanine and L-arginine doped KDP crystals with increase in the radiation dose. A considerable change in the values of RI was observed due to irradiation. The SHG efficiency of LACC crystals were found to decrease with increase in radiation dose where as in case of L-alanine doped KDP crystals, the SHG efficiency was found to increase with increase in radiation dose.
Chemical Science Transactions, 2014
A chalcone derivative, 1-(5-bromothiophen-2-yl)-3-(2,3-dimethoxyphenyl)prop-2-en-1one (BTDMP), ha... more A chalcone derivative, 1-(5-bromothiophen-2-yl)-3-(2,3-dimethoxyphenyl)prop-2-en-1one (BTDMP), has been synthesized and grown as a high-quality single crystal by the slow evaporation solution growth technique. The compound was characterized by FT-IR and NMR studies. The crystal has been subjected to single-crystal x-ray diffraction studies and cell parameters of the crystal were determined. The title compound crystallizes in monoclinic system with a centrosymmetric space group P21/c, with unit cell parameters a= 11.6473(6) Å, b= 8.5651(5) Å, c= 14.4829(8) Å, α= 90 ο , β= 99.853(2) ο , γ = 90 ο and V= 1423.51(14) Å 3. The thermal stability of the crystal was determined from DSC curve. The grown crystals were characterized for their optical transmission and mechanical hardness. The potential of these crystals for NLO applications were studied using molecular hyperpolarizability calculations using MOPAC 2012.
AIP Conference Proceedings, 2011
A potentially useful nonlinear optical (NLO) organic material, 1-(5-chlorothiophen-2-yl)-3-(24,5-... more A potentially useful nonlinear optical (NLO) organic material, 1-(5-chlorothiophen-2-yl)-3-(24,5-trimethoxyphenyl)prop-2-en-1-one(CTTMP), has been synthesized and grown as a high-quality single crystal by the slow evaporation technique. The grown crystals were characterized by UV-visible spectroscopy. The material has thermal stability up to its melting point. Single beam Z-scan technique was employed to study the third order NLO properties of the material.
Journal of Molecular Structure, 2013
ABSTRACT A new potentially useful nonlinear optical (NLO) organic material, 1-(5-bromothiophen-2-... more ABSTRACT A new potentially useful nonlinear optical (NLO) organic material, 1-(5-bromothiophen-2-yl)-3-(4-nitrophenyl)prop-2-en-1-one (BTNP), has been synthesized and grown as a high-quality single crystal by the slow evaporation technique. The grown crystals were chemically characterized by FT-IR and NMR studies. The grown crystal has been subjected to single-crystal X-ray diffraction studies and cell parameters of the crystal were determined. The title compound crystallizes in triclinic system with a noncentrosymmetric space group P1, with unit cell parameters a = 4.8093(4) Å, b = 5.9428(6) Å, c = 11.5153(11) Å, α = 94.999(4), β = 95.780(3), γ = 96.396(4) and V = 323.79(5) Å3. The thermal stability of the crystal was determined from DSC curve. The grown crystals were characterized for their optical transmission and mechanical hardness. The second harmonic generation (SHG) efficiency of the crystals was obtained by powder technique using Nd:YAG laser and is found to be four times that of urea.
Journal of Crystal Growth, 1998
Acta Crystallographica Section E Structure Reports Online, 2012
Acta Crystallographica Section E Structure Reports Online, 2011
Acta Crystallographica Section E Structure Reports Online, 2002
ABSTRACT The title compound, C8H6Cl3NO, also known as N-(2,4,5-trichlorophenyl)acetamide, is an o... more ABSTRACT The title compound, C8H6Cl3NO, also known as N-(2,4,5-trichlorophenyl)acetamide, is an organic non-linear optical material. It crystallizes in the monoclinic system, in the non-centrosymmetric space group Pn.
Acta Crystallographica Section E Structure Reports Online, 2002
ABSTRACT The title compound, C11H15NO, also known as N-(2,4,6-trimethylphenyl)acetamide, is a... more ABSTRACT The title compound, C11H15NO, also known as N-(2,4,6-trimethylphenyl)acetamide, is an organic non-linear optical material. It crystallizes in the monoclinic system, in a non-centrosymmetric space group Pn.
Acta Crystallographica Section E Structure Reports Online, 2002
ABSTRACT The title compound, also known as N-(3-nitrophenyl)acetamide, C8H8N2O3, is an organic... more ABSTRACT The title compound, also known as N-(3-nitrophenyl)acetamide, C8H8N2O3, is an organic non-linear optical material. It crystallizes in the monoclinic system in the chiral space group P21, and there are four independent molecules in the asymmetric unit.
Acta Crystallographica Section E Structure Reports Online, 2011