Paramagnetic Resonance of Mn⁺⁺ Associated with Impurities in Alkali Chlorides

Abstract

The paramagnetic resonance absorption of Mn ++ ions associated with the impurities of fluorine or divalent anions has been investigated in the single crystals of NaCl and LiCl. A resolved fine structure was observed in a “not quenched crystal” and it did not fade into a broad single line in contrast with the spectra of Mn ++ ions which had been usually observed in alkali halides. The ground level splitting parameters have been determined in the spin Hamiltonian D S 1 2 + E ( S 2 2 - S 3 2 ) as follows: D =(-420±1)·10 -4 cm -1 , | E |=(65±1)·10 -4 cm -1 for Mn ++ –F - , D =(-511±5)·10 -4 cm -1 , | E |=(25±5)·10 -4 cm -1 for Mn ++ –X - , a manganese divalent anion pair, in NaCl, and D =(-672±5)·10 -4 cm -1 , | E |=(12±3)·10 -4 cm -1 for Mn ++ –X - in LiCl, the principal axes of the spin Hamiltonian being in nearly agreement with the cubic axes of the crystal. The large value of D suggests the existence of the strong attractive force between Mn ++ and impurity ion.