B. J. Reddy

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.

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.

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.

Optical and EPR studies of iron bearing phosphate minerals: satterlyite and gormanite from Yukon Territory, Canada

The iron phosphate minerals satterlyite and gormanite have been investigated by EPR and optical absorption studies. The optical results indicate the presence of ferrous and ferric ions in both minerals. In gormanite the site symmetry of Fe(III) is near octahedral whereas in satterlyite it is tetragonally distorted. On the other hand, the Fe(II) ions are in tetragonally distorted octahedral site in both minerals. In satterlyite the EPR results indicate the presence of the ferric ion in a tetragonally distorted state together with a small percentage of Mn(II). Crystal field (Dq) and interelectronic parameters (B and C) are evaluated.

Optical and EPR spectra of libethenite mineral

Abstract The optical absorption and EPR spectra of libethenite Cu2(PO4)(OH) of Southern Shaba, Zaire are studied. The optical absorption bands are observed at 12190, 10525 and 8545 cm−1, The octahedral field parameter Dq and tetragonal field parameters Ds and Dt are found to be 1053, 1458 and 542 cm−1, respectively. The EPR spectrum of the mineral contains unresolved copper hyperfine lines due to the high percentage of the paramagnetic ion and a radical presumably PO2 4-. The orbital reduction parameters have also been calculated.

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.

Detailed spectroscopic studies on cornetite from southern shaba, zaire

The optical, EPR and IR spectral analyses of copper bearing cornetite mineral of Southern Shaba, Zaire have been made at room temperature. The spectra are characteristic of doubly ionised copper ion in tetragonally distorted pyramidal symmetry. Chemical analysis supports the presence of copper as major composition in the mineral.

Cu(II), Mn(II) in tetragonal site in chrysocolla

Chrysocolla samples from two regions are studied spectroscopically to ascertain the site symmetries of the transition metal ions present in them. The results indicate the tetragonal site symmetry for Cu(II) and Mn(II). The crystal field and spin Hamiltonian parameters are evaluated.

Spectroscopic studies of a LiRbB4O7:Cu(II) crystal grown by the Czochralski technique

A copper-doped LiRbB4O7 crystal was grown by the Czochralski technique. Powder X-ray, EPR and optical absorption studies were carried out. The results and discussion of the copper doped LiRbB4O7 crystal indicate that the copper ions enter the host lattice by replacing Li ions. The Cu(II) ion spectrum is characteristic of a tetragonally elongated octahedral site. Lattice and spin-Hamiltonian parameters were evaluated. The bonding parameters indicate that the bonding between copper and the ligands is partly covalent.

Structural and spectral studies of ZnKPO4.6H2O crystals

Zinc Potassium Phosphate Hexahydrate (ZPPH) is analogous to naturally occurring struvite. ZPPH crystals are grown by slow evaporation technique. These crystals are characterised by x-ray and infrared studies. Powder x-ray pattern indicates the orthorhombic crystal structure analogous to struvite with unit cell parameters a = 5.964, b= 5.808 and c= 12.495 A. Infrared spectrum is characteristic of H 2 O and PO 4 3- radicals.