Y.P. Reddy

Spectroscopic studies of transition metal doped sodium phosphate glasses

Optical absorption and EPR spectra of Co2+ and Ni2+ doped sodium phosphate glasses have been investigated. Crystal field parameters and g values are determined. For Co2+ doped glass Dq=890, B=700, C=4125 cm−1 and g values of 4.23 and 2.04 at 20 K, for Ni2+ doped glass Dq=890, B=770, C=3700 cm−1 and a g value of 2.28 at room temperature were found. Correlating the optical and electron paramagnetic resonance data suggests the bonding between transition metal ions and ligands as ionic in nature.

EPR and optical studies on transition metal doped LiRbB4O7 glasses

Abstract Electron paramagnetic resonance and optical investigations of copper and chromium doped LiRbB 4 O 7 glasses are carried out. From the results and discussions, it is predicted that both the transition metal ions exhibit octahedral environment. In the case of Cr 3+ , the site symmetry is near octahedral, whereas in the case of Cu 2+ , it is tetragonally distorted octahedral environment. Crystal field, spin-Hamiltonian and bonding parameters are evaluated. The bonding parameters are suggesting ionic.

Site symmetry of Mn(II) and Co(II) in zinc phosphate glass

Abstract Optical absorption and EPR spectra of Mn(II) and Co(II) doped zinc phosphate glasses have been investigated. Crystal filed parameters and g values are determined. For Mn(II) doped glass the values are Dq=850, B=850, C=2975 cm −1 and g values are around 2 at room temperature (RT). For Co(II) doped glass, Dq=890, B=700, C=4100 cm −1 and g=4.45 and 2.06 at liquid nitrogen temperature. The optical and EPR data has been correlated.

Spectroscopic studies of copper-doped ARbB4O7 (A=Na, K) glasses

Abstract EPR and optical absorption investigations are carried out at room temperature on copper-doped ARbB4O7 (A=Na, K) glasses. The results indicate that the copper ions (Cu2+) enter the glass matrix into a tetragonally elongated octahedral site. Crystal field and spin-Hamiltonian parameters are evaluated. The bonding parameters indicate that bonding between the metal ions and ligands is partially covalent.

Mixed alkali effect and optical properties of Ni2+ doped 20ZnO + xLi2O + (30 − x)Na2O + 50B2O3 glasses

Optical and physical properties of Ni2+ doped 20ZnO+xLi2O+(30-x)Na2O+50B2O3 (5≤x≤25) glasses are carried out at room temperature. Powder XRD pattern of all the glass samples confirms the amorphous nature. Several physical parameters are evaluated for all the glasses with respect to the composition. The optical absorption spectra confirm the site symmetry of the Ni2+ doped glasses are near octahedral. Crystal field and inter-electronic repulsion parameters are also evaluated. It is interesting to observe that the optical band gap and Urbach energies exhibit the mixed alkali effect. The FT-IR spectral investigations of Ni2+ doped glasses exhibit characteristic vibrations of BO3 and BO4 units.

Orthorhombic Site Symmetry of Cr3+ in ZnNH4PO4 6H2O Crystals

Spectroscopic investigations of Cr 3+ doped ZAPH are carried out. From the nature of optical absorption bands and their splittings at the liquid nitrogen temperature, the site symmetry of the Cr 3+ in ZAPH is attributed to orthorhombic distortion.

Synthesis and spectroscopic characterization of Mn(II) doped organic amine templated chlorocadmiumphosphate CdHPO4Cl · [H3N(CH2)6NH3]0.5 crystals

Chlorocadmiumphosphate CdHPO4Cl · [H3N(CH2)6NH3]0.5 crystals doped with Mn(II) are grown at room temperature via organic amine template method and characterized by spectroscopic techniques to obtain information on the nature of the incorporated Mn(II). Powder X-ray diffraction patterns of the sample are indexed to monoclinic cell and average crystalline size is found to be around 55 nm. The optical absorption spectrum exhibits various bands which are characteristic of Mn(II) in distorted octahedral site symmetry, confirmed by characteristic resonance signal at g = 2.018 observed in the EPR spectrum. Fourier transform infrared spectrum shows the specific vibrations of phosphate and organic molecules. Thermal curves indicate that the crystal is stable at 307°C; above this temperature crystal structure disintegrates due to removal of the organic amine template.

Spectral investigations of Cu2+ doped beta-barium borate nanopowder by the co-precipitation method

A Cu2+ doped beta-barium borate nanopowder has been synthesized using the co-precipitation method. The average crystallite size of the present system is evaluated at 68 nm and the lattice cell parameters are calculated from x-ray diffraction data. Optical absorption spectral data reveal that the Cu2+ ions are in a tetragonally distorted octahedral site in the host lattice. Direct, indirect and Urbach energies are calculated with the absorption edge technique. Electron paramagnetic resonance results confirm that the Cu2+ ions enter a tetragonally elongated octahedral site at room temperature. The crystal field and spin-Hamiltonian parameters are also evaluated. Fourier transform infrared spectroscopy confirms the vibrational bands of Ba–O and B–O in the system.

Synthesis and spectroscopic characterization of Cu(II) containing chlorocadmiumphosphate Cd(HPO4)Cl·[H3N(CH2)6NH3]0.5 crystals

Chlorocadmiumphosphate Cd(HPO(4))Cl·[H(3)N(CH(2))(6)NH(3)](0.5) crystals containing Cu(II) ions have been successfully synthesized at room temperature by using organic amine 1,6-diamino hexane as a template. The samples are characterized by X-ray powder diffraction, Thermal and spectroscopic studies. These are crystallizes in the monoclinic crystal system with cell dimensions: a=1.7697, b=0.6576, c=1.9026nm and β=106.5°. FT-IR spectrum showed the absorption bands related to PO(4), NH(3)(+) ions and other organic molecule vibrations originated from the templated molecule. The prepared crystals are stable at room temperature and as well as up to around 300°C which were confirmed by thermal analysis. Optical absorption and EPR studies suggest that Cu(II) ion enters in to the lattice as tetragonally distorted octahedral symmetry, for which crystal field and spin-Hamiltonian parameters are calculated. Bonding parameters are suggesting that there exists partial covalent nature between Cu(II) ions and ligands.

Spectroscopic Investigations on Co(II) Doped ZAPH and CAPH Crystals

Optical and EPR spectra of Co(II) doped ZAPH and CAPH crystals are carried out at room and low temperatures. The results of optical absorption studies of Co(II) ion suggest near octahedral site symmetry. The crystal field ( Dq ) and inter-electronic repulsion parameters ( B and C ) are evaluated. Co(II): ZAPH: Dq = 980, B = 870 and C = 3830 cm m 1 , Co(II): CAPH: Dq = 960, B = 890 and C = 4060 cm m 1 . The results of EPR spectra reveal that the Co(II) ion exhibits slightly distorted octahedral site at 11.52 K. The spin-Hamiltonian parameters are evaluated.