Optical Absorption Spectra Of Cr3 Research Articles

Absorption and emission properties of ruby (Cr:Al2O3) single crystal

Absorption and emission measurement were made on ruby (Cr:Al2O3) crystal with 0.5 wt. %). The results for optical absorption spectra of Cr3+:Al2O3 single crystal are shows two strong absorption bands at 408 nm and 558 nm in the range spectrum between 390 nm and 600 nm, meanwhile three broad absorption bands at 205 nm, 227 nm and 255 nm in range spectrum between 190 nm and 370 nm. The emission band when excited by UV light at 205 nm, 227 nm and 255 nm were detected and centered at 321 nm. The emission band by the excitation of 408 nm was found at 465 nm, 671 nm, 692 nm and 710 nm. Meanwhile, the emission band under the excitation of blue light at 490 nm was detected at 671 nm, 692 nm and 710 nm. The emission band at 671 nm, 688 nm, 695 nm and 710 nm were detected from excitation by green light with wavelength at 532 nm and 558 nm.

Modeling of Cr3+ doped d-gluconic acid monohydrate

Zero field splitting parameters (ZFSPs) D and E of Cr3+ ion doped d-gluconic acid monohydrate (DGAM), C6H12O7H2 O are determined using the superposition model. The theoretical ZFSPs for Cr3+ in DGAM single crystal are compared with the experimental values obtained by the electron paramagnetic resonance. There is a good agreement between the two. The energy band positions of the optical absorption spectra of Cr3+ in DGAM single crystal calculated with the crystal field analysis package are in good match with the experimental values.

Zero field splitting parameters of Cr3+ doped potassium sodium dl-tartrate tetrahydrate

The zero field splitting parameters (ZFSPs) D and E of Cr3+ ion doped potassium sodium dl-tartrate tetrahydrate (PSTT), KNaC4H4O6·4H2O are calculated using the superposition model. The theoretically calculated ZFSPs for Cr3+ in PSTT crystal are compared with the experimental values obtained by electron paramagnetic resonance. Theoretical ZFSPs are in good agreement with the experimental values. The energy band positions of optical absorption spectra of Cr3+ in PSTT single crystal calculated with the CFA package agree well with experimental values.

Optical, magnetic and electrical properties of multifunctional Cr3+: Polyethylene oxide (PEO) + polyvinylpyrrolidone (PVP) polymer composites

Multifunctional polymer composite films of PEO + PVP and also doped with Cr3+ ions in different concentrations have been synthesized by a solution casting method. The semi-crystalline nature of the polymer films was confirmed by XRD studies. Raman spectral analysis confirms the complex formation of the polymer with dopant ions. The optical absorption spectrum of Cr3+ doped polymer exhibits three absorption bands pertaining to Cr3+ ions in octahedral symmetry. From the absorption spectrum, Racah parameters were evaluated. The red emission at 614 nm (4T2g→4A2g) has been observed for the Cr3+: PEO + PVP polymer under the UV excitation. EPR spectra of Cr3+ ions doped polymers at different concentrations of Cr3+ ions exhibit resonance signals which are characteristic of Cr3+ ions in the octahedral symmetry. Cr3+: PEO + PVP revealed the superparamagnetic nature based on the trends on Vibrational Sample Magnetometer profiles. Cr3+(0.1 wt%): PEO + PVP polymer reveals high ionic conductivity in the order of 1.14 × 10−5 S/cm at 373 K. Dielectric constant behaviour has also been analysed with respect to frequency.

Theoretical calculation of zero field splitting parameters of Cr3+ doped ammonium oxalate monohydrate

Zero field splitting parameters (ZFSPs) D and E of Cr3+ ion doped ammonium oxalate monohydrate (AOM) are calculated with formula using the superposition model. The theoretically calculated ZFSPs for Cr3+ in AOM crystal are compared with the experimental value obtained by electron paramagnetic resonance (EPR). Theoretical ZFSPs are in good agreement with the experimental ones. The energy band positions of optical absorption spectra of Cr3+ in AOM crystal calculated with CFA package are in good match with the experimental values.

Theoretical investigation of zero field splitting parameter of Cr3+ doped diammonium hexaaqua magnesium sulfate

The zero field splitting parameter D of Cr3+ doped diammonium hexaaqua magnesium sulfate (DHMS) are calculated with perturbation formula using crystal field (CF) parameters from superposition model. The theoretically calculated ZFS parameters for Cr3+ in DHMS single crystal are compared with the experimental value obtained by electron paramagnetic resonance (EPR). The theoretical ZFS parameter D is similar to that from experiment. The energy band positions of optical absorption spectra of Cr3+ doped DHMS single crystal are calculated with CFA package, which are in good match with experimental values.

EPR, optical and physical properties of chromium ions in CdO–SrO–B2O3–SiO2 (CdSBSi) glasses

Chromium ions doped 10CdO–(20−x) SrO–50B2O3–20SiO2 (x=0.5, 1.0, 1.5, 2.0, 2.5mol%) (CdSBSi) glasses have been studied by using Electron Paramagnetic Resonance (EPR) and optical absorption techniques at room temperature. Powder XRD pattern of all the samples confirms amorphous nature of the glass. The low field spectral line of the EPR spectrum of chromium ions in CdSBSi glass is attributed to isolated Cr3+ ions and the high field spectral line is assigned for exchange of coupled pairs Cr3+ ions in all these glasses. The optical absorption spectra of Cr3+ ions in these glasses shows single broad band characteristic of Cr3+ ions in near octahedral symmetry. From this optical absorption spectral data the crystal field parameter (Dq) is evaluated from ultraviolet absorption edges, the optical band gap and Urbach energies are evaluated. The results assert that the optical band gap energy values are depended quite sensitively on added chromium content. The FT-IR spectral investigations of chromium ion doped glasses exhibits characteristic vibrations of BO3 units. Several physical parameters are also evaluated for these glasses with respect to the composition.

EPR and optical absorption studies of Cr3+ ions in alkaline earth alumino borate glasses

Electron paramagnetic resonance (EPR) and optical absorption spectra of Cr3+ ions in Calcium alumino borate (CaAB) glasses have been studied. The EPR spectra exhibit weak resonance signal at g ≈ 4.50 and intense resonance signal at g ≈ 1.98. A sharp resonance signal at g ≈ 1.97 was also observed at lower concentrations of chromium. The concentration dependence of the linewidth of the resonance signal at g ≈ 1.98 suggests the formation of Cr3+ ion clusters by magnetic superexchange interactions. The temperature dependence of the peak to peak intensity and the linewidth of the resonance signal at g ≈ 1.98 suggests that the exchange interactions between Cr3+ ions in the present sample were antiferromagnetic in nature with Neel temperature, TN = 233 K. From the number of spins participating in the resonance at g ≈ 1.98, the paramagnetic susceptibility (χ) was calculated at different temperatures (233–295 K). A plot of 1/χ and T was found to obey Curie-Weiss law with negative Curie temperature. By measuring the relative intensities of the resonance signal at g ≈ 1.98, at different temperatures, the value of antiferromagnetic coupling constant (J) has been estimated. The optical absorption spectrum of chromium doped CaAB glass exhibits four bands, characteristic of Cr3+ ions, in nearly octahedral symmetry. From the band positions, the crystal field splitting parameter, Dq and the Racah interelectronic repulsion parameters, B and C were evaluated. The optical band gap (Eopt) and the Urbach energy (ΔE) were calculated from the ultraviolet absorption edges.

EPR and optical absorption of Cr3+ ions in ternary K2SO4-Na2SO4-ZnSO4 glasses

Electron paramagnetic resonance (EPR) spectrum of Cr3+ ions doped ternary K2SO4-Na2SO4-ZnSO4 glasses has been studied at different temperatures. The low field spectral resonance lines of the EPR spectra of Cr3+ ions in K2SO4-Na2SO4-ZnSO4 glasses are attributed to isolated Cr3+ ions whereas the high field spectral resonance line is attributed to exchange-coupled pairs of Cr3+ ions. The optical absorption spectrum of Cr3+ ions doped glass shows two broad bands characteristic of Cr3+ ions in octahedral symmetry. From the optical spectrum, the crystal field parameter (Dq) and the Racah interelectronic repulsion parameters (B and C) have been evaluated. From the EPR and optical spectral data, it is concluded that the site symmetry arround Cr3+ ions is octahedral and the nature of bonding is predominantly covalent in nature.

Electron paramagnetic resonance and optical absorption spectra of Cr3+ ions in fluorophosphate glasses

Electron paramagnetic resonance and optical absorption studies of Cr3+ ions in fluorophosphate glasses have been carried out at room and low temperatures. The EPR spectra exhibit two resonances at g≈4.67 and g≈2.0. These resonances are attributed to isolated Cr3+ ions and exchange coupled Cr3+ pairs respectively. The EPR spectra were also studied at various low temperatures. The numbers of spins are found to be increasing with decreasing temperature. For the first time, the magnetic susceptibility X was calculated from the EPR data. It was also observed that as temperature decreases X increases in accordance with Curie's law. The line width of the g≈2.0 resonance was found to be decreasing with increasing temperature which confirms the pairing mechanism between Cr3+ ions. The exchange coupling constant J between Cr3+ ions was calculated from the relative intensities of g≈2.0 resonance line at various temperatures. The optical absorption spectrum exhibits four bands, characteristic of Cr3+ ions in octahedral symmetry. The crystal field parameter Dq and the Racah interelectronic repulsion parameters B and C were evaluated.

Optical absorption spectrum of Cr3+ions in sodium ammonium sulphate dihydrate single crystal

Abstract Optical absorption spectrum of Cr3+ ions doped in sodium ammonium sulphate dihydrate single crystal has been studied both at room and liquid nitrogen temperatures. The observed bands were explained satisfactorily assuming octahedral symmetry for the Cr3+ ion in the crystal. The crystal field parameters Dq = 1750 cm−1, B = 735 cm−1 and C = 3220 cm−1 are found to give a good fit to the observed band positions.

Electron Paramagnetic Resonance and optical absorption spectra of Cr3+ in zinc maleate tetrahydrate single crystals

Abstract Electron Paramagnetic Resonance (EPR) and optical absorption spectra of Cr 3+ ions doped in single crystals of zinc maleate tetrahydrate (ZMTH) have been studied at room temperature (300 K). The EPR spectra exhibit a group of three fine structure transitions, characteristic of the Cr 3+ ion. From the observed EPR spectra, the spin-Hamiltonian and zero-field splitting parameters have been determined. The optical absorption spectrum exhibits two broad bands characteristic of Cr 3+ ions in octahedral symmetry. From the observed spectrum, the crystal field parameters have been evaluated.

Optical absorption spectrum of Cr3+ in natural ruby

Two sharp line-like bands calledN andR lines on the red side, a close doublet (B lines) on the violet side and two broad bands are observed for natural ruby. At liquid air temperature the splitting ofR line was found and also three sharp-bands calledR, R′ andB lines are identified with spin-forbidden transitions of2E,2T1 and2T2. The two broad bands calledU band andY band are assigned accordingly to the spin-allowed transitions4T2 and4T1 respectively. The observed bands of natural ruby have been attributed to Cr3+ ion in an octahedral environment with trigonal distortion. The crystal field parameters which gave a good fit to the observed band positions areB=732 cm−1,C=4.25B,Dq=1830 cm−1,V=−1996 cm−1 andλ=34 cm−1.

Optical Absorption Spectrum of Cr3+ Ions Doped in CsCl

AbstractThe optical absorption spectrum of Cr3+ ions doped in CsCl is studied at room and liquid nitrogen temperatures. Assuming tetragonal site symmetry for the Cr3+ ion, the band maxima are successfully fitted with the theoretical energy equations of a d3 configuration immersed in a tetragonal ligand field, including full configuration interaction but neglecting spin—orbit perturbation.

Optical Spectra of Chromium in Mixed Alkali Silicate Glasses

As an approach to the mixed alkali effect in glass, the optical absorption spectra of Cr3+ were determined in mixed alkali silicate glasses. The values of the crystal field strength Dq and the Racah parameters B and C for the glasses were calculated from the observed band positions. The crystal field strength Dq is plotted in Fig. 1 against alkali concentration ratio, R1/(R1+R2) where (R1, R2)=(Li, Na), (Na, K) or (K, Li). The curves in Fig. 1 show that Dq deviates downwards from linearity predicted by combining the values for the end members, i.e., there is a minimum for Dq. The behavior in the glasses shown by curves in Fig. 1 may be interpreted based on the presence of mixed alkali effect.

Elektronen-Spin-Resonanz und optische Untersuchungen an Cr-dotierten Y-Ti-Pyrochlor-Einkristallen Y2Ti2O7

Single crystals of Y2Ti2O7, which crystallizes with the pyrochlore-structure, have been grown by the flux method with PbO -PbF2. The cubic lattice constant is a = (10.0896 ± 0.0014) Å. The free O II-parameter x= -0.0788 ± 0.0005 was determined from X-ray and neutron diffraction data. The ESR spectrum of Cr-doped Y2Ti2O7 single crystals has been observed at X- and Q-band. Cr3+ occupies Ti4+-sites (Symmetry D3d). We obtained the following parameters of the spin Hamiltonian g∥ = 1.9743 ± 0.0005, g⊥ = 1.9767 ± 0.0008 , |D| = 0.954 ± 0.007cm-1. The optical absorption spectrum of Cr3+-doped Y-Ti-pyrochlore shows the U-band (4A2 → 4F2) at (19200 ± 100) cm-1. The R-lines have been studied with fluorescence methods: R1-line E(2E) → 4A2 at (13 930 ± 1 ) cm-1; R2-line 2A(2E) → 4A2 at (14 002 ± 1) cm-1 . The splitting of 72 cm-1 indicates a relatively large trigonal component of the crystal field.