Spectroscopic investigation and simulation of the crystal field effect as well as paramagnetic behavior of K2La1−xPrxCl5 ternary chlorides

Abstract

A series of potassium lanthanum praseodymium ternary chlorides, K 2 La 1Àx Pr x Cl 5 , (0.02 6 x 6 0.15) single crystals was grown with Bridgman techniques. The structures of the mixed crystals were found isotypic with that of K 2 PrCl 5 and K 2 LaCl 5 . The high resolution absorption, luminescence and excitation spectra were recorded at 4, 77 and 293 K. Broad band emission of Pr 3+ reabsorbed by the 3 H 4 ! 3 P J , 1 D 2 transitions was observed simultaneously with the emission from the 3 P 0 level after excitation in the UV region. The 4f 1 5d 1 level scheme derived from the absorption, excitation spectra and from VUV synchrotron excitation was partly established. The 4f 2 energy level scheme of the Pr 3+ ion in K 2 PrCl 5 consisting of 86 (out of 91) Stark components determined from the absorption and emission spectra was simulated by using a phenomenological crystal field model. The model including eight free ion and nine crystal field parameters (according to the C 2v symmetry) yielded a rms deviation of 17 cm À1 between the experimental and calculated energy level schemes. Magnetic susceptibility measurements were carried out between 2 and 298 K. Good agreement was obtained between the experimental and calculated paramagnetic susceptibilities as a function of temperature by using the van Vleck formalism and the energies and wave functions derived from the spectral data.

Energy-level calculations for Pr3+ in K2LaBr5 host

“…[11,12]. The crystal under investigation are isostructural to the earlier reported K 2 PrCl 5 , which enables the study of the trends in the optical properties and crystal-field parameters in the Cl → Br series [5,6,13,14].…”

“…Energy level scheme of the Pr 3+ ion doped into K 2 LaBr 5 host lattice is proposed and comparison with results of CF analysis and optical behaviour reported earlier for K 2 (La, Pr)Cl 5 crystal [5] is presented. The starting set of CF parameters was calculated directly from the X-ray structural data using the Newman's superposition model (SPM) [10].…”

“…The decay times of f-d emission are very short in the range of 10-20 ns. Thus the praseodymium doped compounds could be good candidates both for ultraviolet tunable solid-state lasers and for fast scintillator devices [1][2][3][4][5][6][7][8][9].…”

Spectroscopy, magnetism and non-radiative processes in heteronuclear Cu:Pr squarate; [Pr2Cu(C4O4)4(H2O)16]·2H2O

“…The splitting of the 3 H 4 → 3 P 0 ; 3 P 1 ; 1 D 2 ; 1 G 4 ; 3 F 4 ; 3 F 3 levels was also clearly determinated. Splitting observed for these levels at high energy range is of the order of magnitude of that observed in K 2 PrCl 5 crystals [17]. Moreover, in 3 H 4 → 3 P 0 electronic transition the vibronic components were detected and assigned basing on the IR spectra [18] (Fig.…”

Excited states dynamics in the ternary praseodymium and ytterbium/praseodymium halides

“…It is important to note that the phonons frequencies of the oxides materials are much higher and the multiphonon relaxation processes are more efficient than in the halides [9][10][11][12]. We have reported recently the spectroscopic and simulation results of the crystal field effects as well as the paramagnetic behaviour of K 2 (La,Pr)X 5 (X=Cl À ,Br À ) ternary halides [13,14]. The excited states dynamics has been also investigated by us [15][16][17].…”