The Microwave Spectroscopy of Paramagnetic Salts; the Spectrum of Chromic Alum

Some measurements on the resonance absorption of chrome alum are analyzed for the purpose of obtaining a quantitative estimate of the splitting of the lowest state of the chromic ion by the electric field in the crystal. It is found that a small cylindrical field in addition to the large cubic field present is sufficient to account for the structure of the absorption curves and that the magnitude of the splitting is 0.15±{}.01 cm^-1. It is pointed out that the methods used in the case of chrome alum can be applied to other similar salts such as iron alum and the hydrated gadolinium salts.