Absorption and emission spectra of U4+ diluted in ThBr4 single crystals

Abstract

The absorption and fluorescence spectra 0~ u 4 + diluted in single crystals of ThBr 4have been measured at room• temperature, 77°K, and

Vibronic spectra ofU4+in octahedral crystal fields

“…Recently, the infrared and visible luminescence of U 4+ in ThBr~ has been reported, without interpretation however. In this crystal the U 4+ ion occupies a D2a site at room temperature but the crystal undergoes a phase transition at 95 K which further reduces the site symmetry [17,18]. It therefore seemed probable that further information on the electronic and vibronic behaviour of the UBr62-ion could be obtained by a search for luminescence from this ion in cubic transparent hosts of the type A2MBr 6 (A = Cs, Rb ; M=Zr, Sn, Te).…”

Electronic spectra of uranium tetrachloride clusters with electron-donor ligands

“…A comparison of the electronic spectra of U 4+ ions in crystals of ThBr 4 , ZrSiO 4 , CaF 2 , etc. [16][17][18][19] shows that there is no correlation between the field parameters of one crystal (e.g., ThBr 4 ) and the analogous characteristics of another (ZrSiO 4 ). Experimental Technique.…”

Thorium Tetrabromide: An Old Compound Restudied by Actinide Chemistry

“…Some data obtained from the study of ThBr 4 : Pa 4+ / U 4+ /Np 4+ single crystals have been [5,30,3] or will be shortly published. Obviously, the spectroscopic experiments started with ThBr 4 : U 4 crystals [5].…”

“…Obviously, the spectroscopic experiments started with ThBr 4 : U 4 crystals [5]. Since the first interpretations were made at a time when the low temperature phase structure was not known, these have been reconsidered recently in the light of the existence of a modulated site at 4 Κ [30].…”

“…The only use of ThBr 4 lay in a study of its crystallographic structure as well as of its main chemical properties compared to other thorium halides. However, the discovery of some unexpected and troublesome physical properties such as luminescence [2], radioluminescence [3], phase transition to an incommensurate modulated structure [4] and its use as a non-magnetic and non-optical active host matrix for the study of electronic properties of tetravalent actinide ions [5], have made ThBr 4 so noteworthy that large quantities of its highly pure crystalline form (as single crystals) have been produced and special equipment has been made to handle this very hygroscopic compound [6],…”