. Carnegie Institution of Washington publication. PHOTOGRAPHIC STUDIES OF LUMINESCENCE. K->5 there is no change in the distribution of intensities that can be detected by this method and no measurable shift of the maximum. This result is in accordance with those recorded in Chapter V and it does not confirm the two-band theory of THE EFFECT OF TEMPERATURE ON THE FLUORESCENCE SPECTRUM. It has recently been shown1 that remarkable changes in the apparent complexity of fluorescence spectra are in some cases produced by changes in the temperature of the substance. To determine whether su
. Carnegie Institution of Washington publication. PHOTOGRAPHIC STUDIES OF LUMINESCENCE. K->5 there is no change in the distribution of intensities that can be detected by this method and no measurable shift of the maximum. This result is in accordance with those recorded in Chapter V and it does not confirm the two-band theory of THE EFFECT OF TEMPERATURE ON THE FLUORESCENCE SPECTRUM. It has recently been shown1 that remarkable changes in the apparent complexity of fluorescence spectra are in some cases produced by changes in the temperature of the substance. To determine whether such changes as could be detected by the present method take place in the fluorescence band of Sidot blende when that sub- stance is excited at different temper- atures a series of photographs were taken, the results of which are shown in Fig. 143. This figure contains four curves corresponding to the fluorescence of vSidot blende at different temperatures. In each case the length of excitation was varied so as to give, approximately, negatives of equal density, hence the dimming of the band at higher tem- peratures is not evident, though it occurred. In fact, the powder almost ceased to exhibit fluorescence when the temperature was raised sufficiently. When the temperature was lowered the powder would again show the same spectrum as before, provided a certain critical temperature had not been exceeded. The .v-axis is changed for each curve, so that the points may be entirely distinct from one another. Curves A, B, C, and D were obtained at temperatures 220, 670, 88°, and 1200 respectively. No shifting of the minimum can be seen. • Dv C B A 0 .50 .54 Fig- 143- 58 .62/i :Xicho1s and Merritt; Physical Review, xxxn, p. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Carnegie Institution of Washington. Was
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