Optical absorption of KZnF₃:Tl⁺and KMgF₃:Tl⁺crystals

Abstract

The absorption spectra of KZnF3:Tl+ and KMgF3:Tl+ crystals have been measured over the energy range 1.5-6.4 eV at temperatures of 10-300 K. A wide absorption band with a clear doublet structure identified as an absorption A band of Tl+ impurity centres is observed for both crystals. The position of the band, its bandwidth and the distribution of absorption intensity between the two components of the band are temperature dependent in the range T>65 K. All features of the absorption spectra of the crystals studied are explained within the frameworks of the conventional theory on the basis of the Frank-Condon principle and the semiclassical picture of crystal lattice vibrations. The band shapes calculated by the Monte Carlo method are in satisfactory agreement with observed ones.

Optical studies of Pb2+ions in a LiBaF3crystal

“…To describe the absorption and luminescence spectra and the luminescence decay properties the semiclassical theory based on the Franck-Condon principle and the Jahn-Teller effect for the excited sp configuration was used. This approach had been applied successfully to the KZnF 3 :Tl + and KMgF 3 :Tl + systems and was described in detail in [6,7]. The model Hamiltonian is taken in the form typical for studies of optical centres formed by impurity s 2ions, which occupy positions with cubic (or nearly cubic) symmetry in crystals:…”

“…Our interest concerns fluoride crystals with the perovskite structure, where ns 2 -ions are located in a 12-fold fluorine surrounding. Previously, we have studied the absorption and luminescence of Tl + ions in KZnF 3 and KMgF 3 crystals [6,7]. In spite of the great similarity of the host lattices the luminescent properties of these crystals differ significantly.…”

“…Within the frame of this work, pure and Pb 2+ -doped LiBaF 3 single crystals were grown. Absorption and luminescence spectra as well as luminescence decay were studied in the temperature range 10-300 K. As the Pb 2+ ion replaces the Ba 2+ ion in the lattice there is no need for charge compensation, and the theory developed earlier [6,7] to explain the luminescent properties of the KZnF 3 :Tl + and KMgF 3 :Tl + systems was readily applied to the LiBaF 3 :Pb 2+ crystal.…”

Synthesis of KZnF\(_{3}\) Phosphors by Co-Precipitation Method

“…Photoluminescence and/or magnetic properties of 3d n ions like Mn 2+ [3,27,40], Mn 4+ [19], Ni 2+ [28,48], Co 2+ [5,45], Cr 3+ [49], Cr 2+ [14,31], Cu 2+ [12], 4f n lanthanides like Yb 3+ [4,25,39], Tm 3+ [41], Dy 3+ [15], Ce 3+ , Eu 2+ [20], Eu 3+ [34], Tb 3+ [9] and ns 2 ion Tl + [2] have been studied quite extensively. KZnF 3 :Tl + is of interest as a promising material for tunable lasers in the UV region [1] and scintillator [2] while KZnF 3 :Co 2+ serves similar purpose in mid infrared region [7,23,33]. Upconversion involving various ion pairs such as Yb 3+ -Mn 2+ [43], Yb 3+ -Er 3+ [22,44], Yb 3+ -Tm 3+ [41], Yb 3+ -Ho 3+ [6], KZnF 3 shows intrinsic luminescence [42] though it does not show any cross-luminescence [10].…”

<em>s</em>¹<em>p</em>¹ Configurational Energy Levels in Different Hosts

“…和 D 带又可以进一步劈裂为 A1、 A2、 B1、 B2、 B3、 C1、 C2、 C3、 D1、 D2 和 D3 带 [9][10][11][12] . 大量的实验数据 [7][8][9][10][11][12][13][14] 显示在不同的基质中, s 1…”