Fluorescence and Absorption of the Uranyl Sulphates

Abstract

The spectra of the uranyl sulphates, when resolved by excitation at the temperature of liquid air, exhibit fluorescence series whose frequency intervals range from 85.7 in caesium uranyl sulphate to 83.0 in potassium uranyl sulphate. The shift towards the violet with increasing molecular weight of the compound is unusually large. The absorption bands extend into group 7 of the fluorescence spectrum without break of interval and there are many reversals where fluorescence and absorption overlap. U RANYL sulphate (UO2SO4.3H2O) and the double uranyl sulphates of the alkaline metals are among the most brilliant of known fluorescent substances. Their spectra are characterized by an unusual complexity of narrow bands brought out by cooling to the temperature of liquid air. The group structure is by no means so obviously uniform as in the case of the compounds considered in previous papers nor is there the marked similarity between the spectra of the double sulphates which has been noted in the discussion of the fluorescence and absorption of the chlorides, nitrates and acetates.There are however certain characteristics common to all the sulphates thus far examined, i.e.,1. Fluorescence at -185 0 vanishes with the group 7 (frequency 2,000 to 2,070), which is the reversing region for this family of salts, and the eighth group lies entirely within the absorption region.2. Absorption of the type having the usual 70-frequency interval, extends without change of interval into group 7. What we have called the heads of the prominent absorption series lie in the region between 2,040 and 2,060 instead of at 2,170 as in the spectra of the acetates.3. The fluorescence groups are distinguished by a strong pair of bands fairly dominant in all the spectra excepting that of the sodium salt. The series formed by the members of shorter wave-length of these pairs was terminated towards the violet, where it meets the head of the corresponding absorption series mentioned above.4. The location of the fluorescence groups in the spectrum of the sulphates, is not approximately the same, for the different salts do not approximate coincidence as is the case with the corresponding acetates. On the contrary, there is, in general, a shift toward the violet with in-

Application of Relativistic Quantum Chemistry to the Electronic Energy Levels of the Uranyl Ion

“…From the 1870s on, many different research groups studied the spectroscopy of uranyl salts. The work up to 1919 was summarized by Nichols and Howes in a (first) book on uranyl spectroscopy. They included much analysis of the properties of the spectra, but noted that “... no satisfactory theory has as yet been evolved, ...”.…”

Spectroscopic Measurements of Temperature with Uranyl Compounds

“…Their absorption and uorescence spectra have been studied for over a century and are summarized in three books. [11][12][13] The spectroscopic properties are due to the strongly bonded uranyl ion (UO 2 1 2 ). All the electrons in the ion are paired in covalent bonds.…”

Зондовая Спектроскопия Комбинационного Рассеяния Света Поликристаллов Ураниловых Соединений

“…Уранилы образует разнообразные комплексы с органическими и неорганическими лигандами. Как показывают расчeты и результаты экспериментальных исследований, частота полносимметричной валентной моды для свободного иона уранила близка к 850 сm −1 [1][2][3]. Присутствие соответствующего комбинационного сателлита в спектрах КР анализируемых веществ может служить надeжным индикатором иона уранила.…”