On the Principle of Combination and Stokes' Law in the X-ray Series

Abstract

New $X\ensuremath{-}\mathrm{Ray}$ Line ${\ensuremath{\gamma}}_{6}$ for Elements Tantalum to Uranium.---The two emission lines ${\ensuremath{\gamma}}_{2}$ and ${\ensuremath{\gamma}}_{4}$ are found to be in reality three lines. The new line ${\ensuremath{\gamma}}_{6}$ has wave-lengths of 1110, 1072, 842, 630 and 593 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}11}$ cm. for Ta, W, Tl, Th and U respectively. In the cases of Ir, Pt and Au it is too near ${\ensuremath{\gamma}}_{2}$ and in the cases of Pb and Bi too near ${\ensuremath{\gamma}}_{3}$ to be separated.New Absorption Lines of the M-series.---${\mathrm{Ma}}_{1}$, ${\mathrm{Ma}}_{2}$ and ${\mathrm{Ma}}_{3}$ have been measured for bismuth, and ${\mathrm{Ma}}_{4}$ and ${\mathrm{Ma}}_{5}$ for thorium and uranium, the wave-lengths being, respectively, 4762, 4569, 3894, 2571, 2388, 2385 and 2228 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}11}$ cm.Identification of the Line for Tantalum and Tungsten.---For all the elements Os to U, the difference in wave-lengths of ${\ensuremath{\beta}}_{2}\ensuremath{-}{\ensuremath{\beta}}_{5}$ is equal to about 29 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}11}$ cm. If this difference is the same for Ta and W also, the ${\ensuremath{\beta}}_{5}$ lines for these elements must be the lines 1220.8 and 1250.6, respectively, instead of those ordinarily assumed.Measurement of $\mathrm{La}$, and ${\mathrm{La}}_{2}$ for Tungsten by a different method gave the same wave-lengths as those found by Duane and Patterson.Relationships between Emission and Absorption $X\ensuremath{-}\mathrm{Ray}$ Spectra.---(1) Stokes's law seemed not to hold in the case of W. It was thought the apparent discrepancies might be due to an error in the measurement of ${\mathrm{La}}_{1}$ and ${\mathrm{La}}_{2}$, but these measurements were found correct; however, the discrepancies disappear if we identify ${\ensuremath{\beta}}_{5}$ with 1220.8 instead of 1212.5 and if we associate ${\ensuremath{\gamma}}_{2}$ and ${\ensuremath{\gamma}}_{3}$ with ${\mathrm{La}}_{3}$ and the new line ${\ensuremath{\gamma}}_{6}$ with ${\mathrm{La}}_{2}$. (2) Relations between frequencies. The frequencies of seven of the L-series lines are each approximately equal to the difference between the frequency of an La-line and that of an Ma-line.