title: EPR and optical absorption studies on VO(2+) ions in sodium citrate single crystals.
abstract: X-band electron paramagnetic resonance (EPR) studies of VO(2+) ions in sodium citrate single crystals have been done at room temperature. Detailed EPR analysis indicates the presence of two magnetically inequivalent VO(2+) sites. Both the vanadyl complexes are found to take up substitutional position. The angular variation of the EPR spectra in three planes ba*, bc and ca* are used to determine principal g and A tensors. For the two sites the spin Hamiltonian parameters are, Site I: g(x)=1.9680, g(y)=2.0053, g(z)=1.9124, A(x)=79, A(y)=76, A(z)=185; Site II: g(x)=1.9650, g(y)=2.0067, g(z)=1.9418, A(x)=78, A(y)=70, A(z)=186 x 10(-4)cm(-1). The optical absorption study is also carried out at room temperature and absorption bands are assigned to various transitions. The theoretical band positions are obtained using energy expressions and a good agreement is found with the experimental values. By correlating EPR and optical data different molecular orbital coefficients are evaluated and the nature of bonding in the crystal is discussed.
authors.affiliation: EPR Laboratory, Department of Physics, University of Allahabad, Allahabad 211002, India. ram_kripal2001@rediffmail.com
authors.forename: Ram
authors.initials: R
authors.lastname: Kripal
authors.forename: Indrajeet
authors.initials: I
authors.lastname: Mishra
mesh_terms: D000042:Absorption; D002412:Cations / Q000737:chemistry; D002951:Citrates / Q000737:chemistry*; D003460:Crystallization; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D008958:Models, Molecular; D055620:Optical Phenomena; D017601:Oxygen Compounds / Q000737:chemistry*; D000077559:Sodium Citrate; D013696:Temperature; D017968:Vanadium Compounds / Q000737:chemistry*
chemical_list: D002412:Cations; D002951:Citrates; D017601:Oxygen Compounds; D017968:Vanadium Compounds; D000077559:Sodium Citrate