Electron transitions in magnetic clusters Mn12-Ac at submillimeter wavelengths

Crystal field transitions inside the ground S = 10 multiplet of magnetic clusters Mn12-Ac have been observed in transmission spectra in the wave number range 3-33 cm(-1). The temperature dependence of the resonance frequencies, line widths and mode contributions to the magnetic permeability at T = 3-35 K are consistent on the whole with a spin S = 10 ground split by a tetragonal crystal field. However, some deviation between the calculated and observed mode contributions at high temperatures suggest the presence of other Mn12-Ac excited multiplets with S not equal 10.