On the Irregularity of the Kα Doublets in the Elements of Lower Atomic Numbers

In this paper attention is drawn to the recent measurements of the separation Δλ of the Kα doublets of the lighter elements from Al(13) to Ge(32) by Siegbahn and Ray and by B\"acklin. From these measurements it appears that the experimentally determined values of ΔνR(Z-3.5)⁴ deviate systematically from those calculated according to the relativity formula of Sommerfeld. This deviation is especially large in the case of the Fe group of elements. In order to account for this deviation it is supposed that the experimentally determined ΔνR=ΔνᵣₑₗR+ΔνmagR. The first term on the right hand side is due to the relativity change in the mass of the radiating electron in the two orbits which produce the relativity doublet, and which can be calculated according to Sommerfeld's formula. The second term is due to the difference in the magnetic energy of the excited atom corresponding to the two different k₂ values of the radiating electron. To calculate this term use has been made of the model which was proposed by Land\'e to explain the relativity doublet on a magnetic basis. According to the calculations it is shown that ΔνmagR(Z-3.5)³=α²14 or 3α²32 according to the interpretation which is given to k₂. The first formula is obtained if k₂ determines the inclination of the orbit of the radiating electron, while the second formula is obtained if k₂ determines the shape of the electron orbit. The mean of the experimentally calculated values agrees better with the second formula.The peculiar behavior of the Kα doublets belonging to the first transition group of elements is accounted for on the assumption that the inner magnetic fields in the atoms of these elements are large and therefore produce greater magnetic separation. It is further shown that the hypothesis, that the M₃₃ sub-level is formed first in this group of elements, and then the M₃₂ sub-level, which was introduced in a previous paper to explain the paramagnetic moments of these elements, receive further support from the above mentioned data.