Impact of Cr3+ substitution on the nephelauxetic ratio and Racah parameter of Cr-Mn-Zn nanoferrites

2021 ◽  
Author(s):  
M. Abdo ◽  
M.S. Sadeq
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Tunable Laser ◽  
Ligand Field ◽  
Optical Absorption Spectra ◽  
B Values ◽  
Racah Parameter ◽  
Low Field ◽  
Optical Applications ◽  
First Time

Abstract For the first time, we present the ligand field splitting (10Dq) nephelauxetic ratio (β), Racah parameter (B) and stability of Cr3+ within Mn–Zn nanoferrite which synthesized using the citrate route. These parameters were determined via optical absorption spectra. The obtained bands in the significance range of optical absorption spectra are wide as well as asymmetric; therefore the deconvolution process becomes a necessary task. The values of 10Dq and B have been estimated from the produced bands. The values of 10Dq are observed to increase from 16366.61 to 16447.37 cm-1 whereas, B values are observed to decrease from 829.81 to 760.80 cm-1 with additional Cr3+ substitution. The increasing 10Dq and decreasing B values, evidence for bonds between Cr3+ ions with their environments became a further covalent (less ionic). Moreover, the values of β are observed to decrease for further Cr3+ substitution. This decrease of β produces less stability between Cr3+ and its ligand. Furthermore, Dq/B values declare that Cr3+ centers are in the low-field sites by a slight tendency towards the high-field sites with further Cr/Fe substitution process. Therefore, it was suggested that Cr3+ substituted Mn–Zn nanoferrites are excellent candidates for diverse optical applications such as a tunable laser.

The optical absorption spectra of certain transition metal ions in muscovite, lepidolite, and fuchsite

1968 ◽  
Vol 5 (1) ◽  
pp. 31-38 ◽  
Author(s):  
G. H. Faye
Keyword(s):  
Transition Metal ◽  
Optical Absorption ◽  
Metal Ions ◽  
Absorption Spectra ◽  
Transition Metal Ions ◽  
Ligand Field ◽  
Optical Absorption Spectra ◽  
Ligand Field Theory ◽  
Octahedral Sites ◽  
Sheet Silicate

The unpolarized optical absorption spectra of the sheet silicate minerals muscovite, lepidolite, and fuchsite have been examined. The spectra, interpreted on the basis of ligand field theory, indicate that all three minerals contain Fe3+ and possibly Ti3+ in octahedral sites. In addition, muscovite is shown to contain octahedrally coordinated Fe2+, lepidolite octahedral Fe2+ and Mn2+, and fuchsite octahedral Cr3+. No evidence was found for transition metals in tetrahedral sites.Some comments are made on the similarity of the spectra of certain of the transition metal ions in several classes of minerals. This leads to the speculation that the cations Fe3+, Mn2+, and Cr3+ may tend to 'mold' their immediate surroundings.

Optical Absorption Spectra and Dynamic Jahn-Teller Effect of V2+ Ions in ZnSe

2008 ◽  
Vol 63 (12) ◽  
pp. 830-838
Author(s):  
Yi-Yang Zhou
Keyword(s):  
Optical Absorption ◽  
Crystal Field ◽  
Absorption Spectra ◽  
Optical Absorption Spectra ◽  
Cubic Crystal ◽  
Racah Parameter ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Tetrahedral Crystal ◽  
Good Agreement

The Hamiltonian matrices for 3d3 ions in a cubic crystal field are introduced, based on a molecular orbital model, including the electronic Coulomb and tetrahedral crystal-field interactions and the spin-orbit coupling. The optical absorption spectra of V2+ ions in ZnSe are studied. Moreover, the various additional levels found close to 5680 cm−1 are considered. These levels are assumed to result from the dynamic Jahn-Teller splitting within the excitation levels 2T2 and 2T1 in ZnSe:V2+. The good agreement between the present results and the experimental observations indicates that the contribution of the covalence reduction factors NE and NT2 and of the Racah parameter A to the optical absorption spectra of V2+ ions in ZnSe is important. However, most of the previous theoretical studies of these spectra in ZnSe:V2+ have neglected the Racah parameter A, based on the classical crystalfield model. A significant charge-transfer effect found in recent works is confirmed in ZnSe:V2+.

The role of dysprosium ions on the physical and optical properties of lithium-borosulfophosphate glasses

2017 ◽  
Vol 31 (13) ◽  
pp. 1750101 ◽  
Author(s):  
Ibrahim Bulus ◽  
S. A. Dalhatu ◽  
R. Hussin ◽  
W. N. Wan Shamsuri ◽  
Y. A. Yamusa
Keyword(s):  
Optical Properties ◽  
Optical Absorption ◽  
Absorption Spectra ◽  
Physical Parameters ◽  
Potential Candidate ◽  
Optical Absorption Spectra ◽  
Absorption Bands ◽  
X Ray ◽  
Nir Absorption ◽  
Optical Applications

Achieving outstanding physical and optical properties of borosulfophosphate glasses via controlled doping of rare earth ions is the key issue in the fabrication of new and highly-efficient glass material for diverse optical applications. Thus, the effect of replacing P2O5 by Dy2O3 on the physical and optical properties of Dy[Formula: see text]-doped lithium-borosulfophosphate glasses with chemical composition of 15Li2O–30B2O3–15SO3–[Formula: see text]P2O5–[Formula: see text]Dy2O3 (where 0.0 mol.% [Formula: see text] mol.%) has been investigated. The glass samples were synthesized from high-purity raw materials via convectional melt-quenching technique and characterized by X-ray diffraction (XRD), energy-dispersive X-ray spectrometry (EDX), density and UV–vis–NIR absorption measurements. The amorphous nature of the prepared glass samples was confirmed by XRD patterns whereas the EDX spectrum depicts elemental traces of O, C, B, S, P and Dy. The physical parameters such as density, refractive index, molar volume, polaron radius and field strength were found to vary nonlinearly with increasing Dy2O3 concentration. UV–vis–NIR absorption spectra revealed seven absorption bands with most dominant peak at 1269 nm (6H[Formula: see text]F[Formula: see text]H[Formula: see text]). From the optical absorption spectra, the optical bandgap and Urbach’s energy have been determined and are related with the structural changes occurring in these glasses with increase in Dy2O3 content. Meanwhile, the bonding parameters ([Formula: see text]) evaluated from the optical absorption spectra were found to be ionic in nature. The superior features exhibited by the current glasses nominate them as potential candidate for nonlinear optical applications.

Electron Paramagnetic Resonance and Optical Absorption Spectra of VO2+ in CsCl Single Crystals

1985 ◽  
Vol 40 (5) ◽  
pp. 511-515 ◽  
Author(s):  
G. Elbers ◽  
G. Lehmann
Keyword(s):  
Optical Absorption ◽  
Absorption Spectra ◽  
Room Temperature ◽  
Ligand Field ◽  
Optical Absorption Spectra ◽  
Paramagnetic Resonance ◽  
Rapid Rotation ◽  
Vanadyl Ion ◽  
Vibrational Progression ◽  
Electron Paramagnetic

In vanadium-doped CsCl crystals grown from aqueous solutions anisotropic EPR spectra due to VO2+ are observed and analyzed at room temperature. Evidence is presented that isotropic spectra of this ion observed in this and other compounds are due to inclusions of growth solution and not to rapid rotation of the vanadyl ion in the solid as normally assumed. At 77 K a well resolved vibrational progression of about 820 cm −1 is observed in the first ligand field band of this ion. The optical absorption spectra indicate the presence of a second valence state of vanadium, most likely V3+, in varying proportions depending on the crystal growth temperature.

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