EPR of Mn2+ in Na2ZnCl4 · 3 H2O

Abstract

The EPR spectrum of Mn2+ in Na,ZnCl4·3 H2O was investigated in the range 100 K ≦T≦300 K. The spectrum can be described by a Spin Hamiltonian with axial symmetry. The g factor is anisotropic, g∥ = 2.0007 ±0.0005; g⊥ = 2.0030 ± 0.0005. The axial crystal field splitting constants are D = (-901.0 ±2.0) -10-4 cm-1, B = (-5.7 ± 2.0) · 10-4 cm-1. The hyperfine splitting constants A = (-74.9 ±0.2)-10-4 cm-1 and A⊥ = (-74.2 ± 0.2) · 10-4 cm-1 have been determined. This corresponds to a Mn2+ ion bond to four Cl- ions within a tetrahedron. Since a large crystal field splitting constant D is observed, a strong axial crystal field at the site of the Mn2+ ion is assumed. From the temperature dependence of the crystal field splitting constant D a dominant phonon frequency of (117 ± 10) · 1011 sec-1 is deduced.