On a complementary scale of crystal-field strength

Abstract

A new measure of the crystal-field strength, complementary to the conventional one, is defined. It is based on the rotational invariants |B k0 | av or | k B k0 | av , k = 2, 4, 6, of the crystal-(ligand)-field (CF) Hamiltonian H CF parametrizations, i.e. on the axial CF parameters modules averaged over all reference frame orientations. They turn out to be equal to H (k) CF av and |H CF | av , respectively. While the traditional measure is established on the parametrization modules or on the second moment of the CF energy levels, the introduced scale employs rather the first moment of the energy modules and has better resolving power. The new scale is able to differentiate the strength of various iso-modular parametrizations according to the classes of rotationally equivalent parametrizations. Using both the compatible CF strength measures one may draw more accurate conclusions about the Stark levels arrays and particularly their total splitting magnitudes.PACS: 71.70.Ch

Capability of the Free-Ion Eigenstates for Crystal-Field Splitting

“…The asphericity A k for and 6 of any electronic state may serve as a reliable measure of its capability for CF splitting produced by the [10,13,14]   2 = 1 2 1 ,…”

“…The k A magnitudes and their possible variations due to the J-mixing of the RS states are thoroughly discussed. An inseparable entanglement of the asphericities k A and the k-components of the CF strength k [9][10][11][12]  [10,13,14], resulting from the orthogonality of the 3-j symbols [3,4] (Equation (1) …”

Crystal structure, energy transfer mechanism and tunable luminescence in Ce3+/Dy3+ co-activated Ca20Mg3Al26Si3O68 nanophosphors

“…Besides, when Dy 3 þ is situated at a low symmetry site (without inversion symmetry), the 4 F 9/2 -6 H 13/2 transition emission is dominant in the visible emission spectrum; when Dy 3 þ is at a high symmetry site (with inversion symmetry), the 4 F 9/2 -6 H 15/2 transition emission is prominent [32,33]. The yellow emission ( 4 F 9/2 -6 H 13/2 ) corresponds to the hypersensitive (forced electric dipole) transition with the selection rule ΔJ¼2 (J: the angular momentum), which is strongly dependent on the chemical environment surrounding Dy 3 þ ions [34,35]. It can be seen from the Fig.…”

Photoluminescence Properties of Dy³⁺-Doped LaOF Nanophosphor for white LED Applications

“…It was observed that PL intensity increases up to 3 mol% Dy 3+ ions and beyond this, the intensity decreases due to concentration quenching. Concentration quenching may occur due to two reasons: (i) the distance between the ions shortens and the interaction of the ions becomes stronger, thus producing energy transfer interaction; (ii) it may be due to crossrelaxation 13,14 . The resultant CIE coordinates were estimated by utilizing the PL emission spectrum.…”