Submillimeter spectroscopy of Mn ₁₂ -Ac magnetic clusters

Abstract

Transitions inside the ground S = 10 multiplet of magnetic clusters Mn12-Ac have been observed in submillimeter transmission spectra measured by means of a quasi-optical backward-wave-oscillator technique in the frequency range ν = 3–33 cm−1. The temperature dependence of the resonance frequencies, linewidths and mode contributions to the magnetic permeability in the range T = 3–35 K are consistent on the whole with a spin S = 10 ground state split by a tetragonal crystal field. However, some deviations between the calculated and observed mode contributions at high temperatures suggest the presence of other Mn12-Ac excited multiplets with S ≠ 10.