RESUMO
We derive the high-temperature expansion of the Helmholtz free energy of the quantum and classical models for the Mn(12)-ac molecule in the presence of a skew magnetic field, including the transverse term in the Hamiltonians, for [Formula: see text] K. In this region of temperature, we show that the transverse term can give a measurable contribution to the x component of the magnetization. We obtain the specific heat per site of a powder sample of Mn(12)-ac under a constant magnetic field. For strong skew magnetic fields (h/D>1), the specific heat differs up to 20% from its value of a crystal sample under purely longitudinal magnetic fields. Finally, we obtain that in the limit [Formula: see text], the values of the classical and quantum specific heat differ; in particular, for [Formula: see text] this difference is 0.96%.