Zero-Field Splitting Parameter of the Mn++ Ion in Glassy and in Polycrystalline Media

An attempt has been made to measure the zero-field splitting parameter of the manganous ion in glassy and polycrystalline media from the relative intensities of the allowed transitions of the EPR hyperfine spectrum. A value of this parameter D=96±5 G was determined for manganous ion in glassy 12N HCl for T≤140°K, and of D=145 G in glassy methnol for T≤118°K. In the crystalline phase, the D term in both cases approximately doubled. A value of D intermediate between that of the glassy phase and the final crystalline phase was found for methanol between temperatures of 120° and 135°K.