Electronic Activation in Crystals: The Heat Capacities of Sm2(SO4)3·8H2O and Nd2(SO4)3·8H2O from 3 to 40° Kelvin

Abstract
The heat capacities of the sulfate octahydrates of neodymium and samarium have been measured from 3 to 40°K. The results have been applied to the study of the electronic energy states of the rare earth ions. The electronic heat capacity of the neodymium ion in the sulfate octahydrate has been determined. The separations of the two electronic energy levels comprising the basic states of both salts have been found to be less than 1 cm—1. The presence of an electronic energy level in Nd2(SO4)3.8H2O at 77 cm—1 above that of the basic state has been substantiated. The statistical weight of this level appears to be twice that of the basic state.