X-RAY 5P EMISSION BANDS OF HEAVY RARE-EARTH METALS.

The 5p emission bands of heavy rare-earth metals of the lanthanum group were studied for the first time in the energy range from 10 to 40 eV. Two bands with intensities in the ratio of about 1:5 were observed and they were due to spin-orbit splitting of the 5p levels 5 p// one-half and 5p//3/////2). The half-width of the O//3(5p//3/////2) band increased on increase in the atomic number from 3 eV for **6**4Gd to 5. 1 eV for **6**9Tm. The relationship between the structure of the 5p emission bands and the valence energy band of the rare-earth metals was analyzed.