Inner Conversion in X-Ray Spectra


IN a recent communication1, Saha and Mukerjie have pointed out that although the transition LII,III LI is not forbidden by quantum mechanics, the X-ray spectral line corresponding to it has never been observed, and they have suggested that the failure to obtain such a line can be ascribed to its complete internal conversion in the M-shell. Such an explanation would appear, however, to be inconsistent with the conclusions reached by Taylor and Mott2 in their recent discussion of the nature of the internal conversion process for -rays. (Clearly the same considerations will apply to the internal conversion of X-rays.) Briefly, stated in terms of the present problem, the conclusion reached is as follows: the presence of the M-electrons increases the number of LIII LI transitions above that to be expected from a direct calculation of the electric moment corresponding to such a transition, the rate of production of such induced transitions being only slightly less than the rate of ejection of the M-electrons, and thus the intensity of the observed X-ray line should be only slightly decreased by the internal conversion.

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  1. 1

    NATURE, 133, 377, March 10, 1934.

  2. 2

    Taylor and Mott, Proc. Roy. Soc., A, 142, 215; 1933.

  3. 3

    Martin, Proc. Roy. Soc., A, 115, 420; 1927.

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