Study with Analytical Equations of Absorption Spectra Containing Interference Dips in Fluoride Glasses Doped with Cr³⁺

Abstract

The optical absorption of Cr(3+)-doped fluoride glasses has been investigated. The lowest energy absorption band (4)A2 → (4)T2 shows distinct interference dips due to spin-orbit coupling between (4)T2, (2)E and (2)T1 excited states. The dips were analyzed using an analytical method proposed by Bussière et al. ( J. Phys. Chem. A 2003 , 107 , 1258 ) based on coupled potential energy surfaces. Then a theoretical crystal-field analysis based on the Racah tensor algebraic method was carried on Cr(3+) ions occupying octahedral site symmetry in the fluoride glasses. Satisfactory correlations were obtained between the experimental and calculated energy levels. The fitting of the interference dips also provided a measure of the spin-orbit coupling constant for Cr(3+) in fluoride glasses, intermediate between the theoretical value calculated for a fluoride crystal and the value deduced from Racah parameters.

New Analysis Model for the Determination of Racah and Crystal-Field Splitting Parameters: Verification and Case Studies

“…12 An investigation of the Racah and crystal-field splitting parameters of the transition metal ions has been carried out theoretically using various techniques, such as systematic semi-empirical ligandfield analysis, 10 ab initio calculation, 13,14 and first-principles calculation. 15,16 Experimentally, Malysa et al 11,17,18 and Maalej et al 19 investigated a variety of Cr 3+ -activated phosphors in view of their potential applications as luminescent converters for red-emitting light sources and further discussed the crystal-field splitting and Racah parameters in conjunction with the Tanabe-Sugano diagram.…”

Tm3+/Cr3+ Codoped Dual‐Phase Transparent Glass‐Ceramics for Light Conversion in Photosynthesis

“…The absorption bands of PG–Tm/Cr at 630 nm and GC–Tm/Cr at 560 nm correspond to the transition of Cr 3+ from ground state 4 A 2 to excited state 4 T 2 . [ 31 ] However, the electrons in the 3d electrons of Cr 3+ ions are not protected by the outer shells, leading to the high sensitivity to changes in the external crystal field. When the Cr 3+ ions transfer from the amorphous glass phase to the crystal phase, the bandgap of the Cr 3+ ions changes with their coordination environment alternation, leading to an obvious blueshift in the absorption band of Cr 3+ after heat treatment.…”

“…Therefore, the existence of the crystal field can strengthen the emission of Cr 3+ ions to a greater extent. [ 31 ] And, an obvious Stark splitting at 454 nm appears in the GC–Tm/Cr after heat treatment. The stronger emission in GC samples can be attributed to the following two reasons: the local environment alternation and suppression in detrimental nonradiative energy transfer.…”

“…However, without the dual‐crystal phase in the Tm 3+ /Cr 3+ codoping systems, the electrons of Tm 3+ ions also transfer from the excited state 1 D 2 to the excited state 4 T 1 of Cr 3+ ions under the excitation of 358 nm, leading to an obvious decrease in luminous efficiency of Tm 3+ ions. [ 30,31 ] And the electrons of Cr 3+ ions will transfer from 4 T 1 state to 4 T 2 state and 4 A 2 state, emitting a broadband spectrum (650–850 nm) located at 704 nm. Consequently, in the Tm 3+ /Cr 3+ homogeneous system, the FRET process from Tm 3+ ions Cr 3+ ions is unavoidable.…”

Racah Parameter Ratio C/B for the 3d3-Configuration Ions Like Mn4+and Cr3+in the Tanabe-Sugano Diagram

“…A theoretical investigation of the Racah parameters and crystal-field strength parameters of the transition metal ions has also been carried out using various calculation techniques, such as systematic semi-empirical ligandfield analysis, 15 ab initio calculation, 16,17 and first-principles calculation. 18,19 Experimentally, Malysa et al [20][21][22] and Maalej et al 23 investigated a variety of Cr 3+ -activated phosphors and discussed these results in conjunction with the Tanabe−Sugano energy-level diagram.…”