114 



FLUORESCENCE OF THE URANYL SALTS. 



TABLE 36. Polarized series at 185 C. continued. 

 URANYL CAESIUM CHLORIDE continued. 



As in these spectra at +20, so at 185 we find the D bands only 

 in the green component, the B bands chiefly in the white component. 



In the white component, at both temperatures, B, C, and A lie 

 toward the violet, E toward the red. At 185, B is doubled in the 

 uranyl ammonium chloride, D in the uranyl chloride. 



To aid in the direct comparison of the spectra at the two tempera- 

 tures, they are plotted together in figure 75, in which diagram may be 

 seen the direction of the shift for each series of the two components. 



The shift is nearly always toward the violet, the only exceptions 

 being the A g and a a series and possibly the A w series in uranyl potas- 

 sium chloride (see fig. 74), the e g and fg series of uranyl ammonium 

 chloride and the A y series of the latter salt. The change is greatest 

 in uranyl caesium chloride and least in the potassium double chloride. 



In general the fluorescence bands shift in the same direction and 

 by the same amount as the related absorption bands, but there are 

 some puzzling exceptions to this rule to be considered in a following 

 section. 



The increased resolution of the spectra upon cooling shows itself in 

 the doubling of many bands which appear single at +20, an effect 

 particularly noticeable in the absorption spectra. (See plate 1, c.) 

 Thus the c a series of the potassium salt tends to double at 2,058.0 



