ee Boe at ae
oO
POLARIZATION
ABSORBANCE (RELATIVE)
18]
|
290
i
300
J
]
320
340
j
360
|.
380
j
=6400
0
WAVELENGTH (mj)
Fic. 139.-—-Absorbance of 1,3,6,8-tetrapheny] pyrene and corresponding polarization of emission
tion at the long-wavelength end of the range is that
of the grating, 410 mp.
SEARCH FOR HIDDEN LEVELS
Several additional compounds have been studied;
also, some of those studied previously have been re-
studied for more complete information. As pointed
out previously, in general it has been found not
worth while to study a compound in a liquid medium
unless the compound has a very short fluorescence
decay time of the order of one nanosecond) because
otherwise depolarization reduces the values to the
point where trends are obscured. Table 66 gives the
additional results to date. The long-wavelength edge
of the first absorption band is given to provide orien-
tation for the reader. Also, to aid in the visualization
of the results, curves are given in Figure 139 of absorption and corresponding polarization of emission