Analysis of the fluorescence bands of the uranyl salts
From some direct experimental evidence, it is concluded that the entire fluorescence spectrum of the uranyl salts arises out of a transition from a single excited state (designated1Πg) to the several vibrational states of two close ground levels (designated1Σg and X) and that the1Πg →1Σg transition is much less favoured than the1Πg-X transition. Theν1 andν2 frequencies taking part in the transition agree with those observed in the Raman and infra-red spectra;ν1 is, however, very much more prominent. The vibrational structure of the1Πg-1Σg transition resembles that of a forbidden transition, while the structure of the other is that of an allowed one. The intensity distribution of the A, B and C bands is explained. No specific explanation of the D bands is given. Van Heel’s analysis is shown to be unsatisfactory.