Masters Thesis

Electron paramagnetic resonance of Mn++ in calcite.

Electron paramagnetic resonance (EPR) is a very useful tool to study atomic structure where energy level differences are on the order of I Oyev to lOOyev. The first successful experiment was performed by Zavoisky in 19^5 (Ref. I). Since then numerous books and articles have been published on EPR studies of various atomic systems which have added to our knowledge of atomic structure. The present paper undertakes a study of M n ++ in a natural calcite (CaCO^) crystal. Thermoluminescence studies of this particular crystalindicated the presence of M n ++ which would be a substitutional impurity in the crystalline lattice for calcium atoms. Hn has an electronic spin of S=5/2 and nuclear spin of 1=5/2 (Hurd, Sachs, and Hershberger, Ref. 2); thus, the spectrum of M n ++ in the crystalline electric field of calcite will have a large number of absorption peaks. Using the spin Hamiltonian, an attempt will be made to identify which absorption line or set of lines correspond to particular terms in the spin Hami1tonian. The technique of EPR need not be applied to the solid state only; any system that an unpaired electron can be subjected to EPR study. F centers, free radicals, and conduction band electrons in metals are just three of the possibilities. In addition to M n + +, an attempt was made to study F centers; however, due to the lack of sensitivity and the inability to produce high concentrations of F centers, no absorption peaks were detected.