$S = 4$ and $S = 5$ SPIN STATES OF THE ANTIFERROMAGNETIC $Mn_{2}$ MOLECULE

Abstract

$MD_{2}$ has been shown to be a van der Waals molecule with the two Mn atoms $(3d^{5}4s^{2})$ antiferromagnetically coupled $(J = -10 cm^{-1})$ to form a $^{1}\sigma_{g}$ lowest $state.^{1} {Mn_{2}}$ can be formed in solid methane or cyclopropane at 12 K without reacting, and warming successively populates the higher $S = 1, 2, 3, 4, 5$ spin states. These hydrocarbon matrices allowed higher temperatures to be reached than in rare-gas matrices with still resolvable spectra so that ESR transitions in $S = 4$ and $S = 5$ could be observed and analyzed. The derived g and D values corroborate the earlier application of the Judd-Owen theory.