Investigation of uranium luminescence in SrB4O7 matrix by time resolved photoluminescence, thermally stimulated luminescence and electron spin resonance spectroscopy

Uranium luminescence in La2Zr2O7: effect of concentration and annealing temperature

“…By contrast, the 900 °C annealed sample showed a single broad peak at ~ 538 nm. The broad band feature observed here resembles the observed for uranium in SrZrO 3 and SrB 4 O 7 hosts with the absence of the regular signatures of the vibronic coupling as observed in case of uranyl (UO 2 2+ ). This rules out the possibility of the formation of uranyl ion in the sample.…”

“…In addition to the well known uranyl ion (UO 2 2+ ), the hexavalent uranium is known to exist as uranates with fourfold (UO 4 2– ) or sixfold geometry (UO 6 6– ). These have been illustrated in some of the recent work from our laboratory .…”

Revealing the oxidation number and local coordination of uranium in Nd 2 Zr 2 O 7 pyrochlore: A photoluminescence study

“…in case of the silicate [3], pyrophosphate [11], borophosphate [12] and borate matrices [13], uranium gets stabilized as uranyl (UO 2 2 þ ), whereas, in case of the tetraborate [14] and zirconate [15] matrices, it was the octahedral uranate species, UO 6 6 À that gets stabilized preferentially. This difference is probably because of U-O bond length.…”

“…Depending upon the crystal filed of host lattice; uranium can stabilize in different forms of U(VI) in solids. Based on some of the recent work from our laboratory it was observed that uranium stabilizes as UO 2 2 þ in Sr 2 SiO 4 , SrBPO 5 , Sr 2 P 2 O 7 , ThO 2 , YBO 3 [3,[11][12][13][14] whereas as UO 6 6 À in SrZrO 3 , SrB 4 O 7 [15,16] etc.…”

Photoluminescence properties of U in SrBPO5 host: Effect of concentration and annealing temperature

“…Another weak but prominent hump in the spectra was observable at 595 nm (16,806 cm À 1 ). These bands are known to be associated with Uranyl emissions [23].…”