ISSN:
0377-0486
Schlagwort(e):
Chemistry
;
Analytical Chemistry and Spectroscopy
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Physik
Notizen:
The temperature-dependent Raman spectra of crystalline uranyl nitrate hexahydrate, UO2(NO3)2 · 6H2O, are reported in the temperature range 15-290 K. A group theoretically consistent assignment of the bands in terms of UO22+, NO3- and H2O vibrations is proposed. The temperature-dependent studies of thermosensitive bands associated with these entities were used to study the previously reported phase transition at 140 ± 5 K and to detect another phase transition at 190 ± 5 K. The latter transition shows up prominently in the temperature-dependent fluorescence studies and is also accompanied by a sharp increase in the Rayleigh scattering. The transition at 190 ± 5 K is triggered by the dynamics of H2O-II and UO22+ whereas that at 140 ± 5 K is associated with the dynamics of H2O-II/NO3-. Both the transitions are of second order.
Zusätzliches Material:
9 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jrs.1250200503
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