Electronic, magnetic, and vibrational properties of the molecular magnet Mn4 monomer and dimer Original Research Article

A new type of the single-molecule magnet [Mn4O3Cl4(O2CEt)3(py)3] forms dimers. Recent magnetic hysteresis measurements on this single-molecular magnet revealed interesting phenomena: an absence of quantum tunneling at zero magnetic field and tunneling before magnetic field reversal. This is attributed to a significant antiferromagnetic exchange interaction between different monomers. To investigate this system, we calculate the electronic structure, magnetic properties, intramolecular and intermolecular exchange interactions using density-functional theory within the generalized-gradient approximation. Our calculations agree with experiment. We find that the calculated threefold symmetric structure is vibrationally stable. We also calculate vibrational infrared absorption and Raman scattering intensities for the monomer which can be tested experimentally.