Abstract
The absorption spectrum of hexagonal Sm(C2H5SO4)3 ·9H2O has been investigated in the temperature range 20° to 295°K. It is found to be simpler than that of the monoclinic SmCl3·6H2O previously reported. This is in agreement with theoretical conclusions that the greater symmetry of the hexagonal lattice should give rise to crystalline fields which would cause the energy levels of Sm+++ ion to be split apart less and to be in some cases more degenerate than would the more unsymmetrical monoclinic lattice. The ethylsulfate lines seem to be related chiefly to three lower levels, the basic one and two which are located higher on the energy scale by 55 and 65 cm1, respectively. Complete figures are given for the ethylsulfate absorption in the visible region. In addition results for the iodide and perchlorate of samarium are summarized. The lower levels found to be most important in these salts are situated at 0, 90, 107 cm1 for the iodide; and 0, 104, 160 cm1 for the perchlorate.