sci3.001.30-ms-02

delta S_a = delta S_i e^{-delta x}= sigma I_o e^{-2delta x}delta x

For a practically infinitely thick crystal altogether

S_a= sigma I _o/2 [delta]

The white spectrum runs steadily for the wave-lengths corresponding
to the K edge of the crystal-substance, and so does the scattering
coefficient is the representation the intensity jump corresponding
to this edge is, if the absorption coefficients on the two sides of the K-edge
are alpha and alpha₊, equal to the reciprocal ratio of these; i.e.

S₊/S_- = alpha_-/alpha₊

This relation has is for the group of elements around Cu 7.4¹,
for Ag about 6; for C₃ and I, with which we
{¹v. d. D. Ph. qes. 1b, 898 (1914)} have to deal, Glocker² gives 5.22 (for Z=54).
The intensity ratio for the first jump on the Duane curve for C₅I₃co 12.0/2.4 = 5.0
{² Glocker P.2.
19,66 (1918) }
The jump the absorption coefficients of the crystal-substances
accordingly gives here almost quantitatively the "curve of the absorption
edge of the characteristic frequency of crystal atoms."

One obtains an entirely similar curve by reflection from the 100-
planes of K I. The job is still simpler, since the renewed occurence of
higher maxima in the higher orders is missing. The ratio of the
absorption coefficients of the I K edge must be less here, since there
is indifferent K mixed in. One obtains by applying the usual
relations

calculated absorption jumps 4.05, 4.06

and reads from the figure the intensity jumps 4.09, 4.2 for the
two pictures of the first order. The agreement again occurs within
the limit of accuracy for the steep maximum of the steep remainder of
the curves.

While the chief point of the phenomenon here is satisfactorily
explained, a measurement of Clark and Duane ( [wie der pepebene] von
Kerr Walter) 110- planes of K I shows a jump of 12 or
13 fold, while the absorption phenomenon here permits
one of only 4.06 fold. Since it appears very remarkable that
in two cases only the theoretical jump is to be expected, and in the
third a 3-times too high jump occurs, it would be very desirable,
in case there isnt an error in the ordinate-figures, to repeat the
measurements.

In regard for order to determine that the peaks coming in in the higher orders of
CsI₃ belong to more closely spaced I-planes, while the special