Theoretical Study of the Magnetic Properties of an Mn12 Single-Molecule Magnet with a Loop Structure: The Role of the Next-Nearest Neighbor Interactions.

The magnetic properties of a Mn12 single-molecule magnet with a loop structure are characterized by a computational study based on density functional theory. A study of the two reported crystal structures of such a complex correctly reproduces the experimental spin ground state. We have analyzed the effect of the choice of spin configurations employed for the calculations, as well as the influence of the inclusion of the next-nearest neighbor interactions on the calculated exchange coupling constants. Quantum Monte Carlo simulations performed with the calculated exchange coupling constants show that the best agreement with the experimental susceptibility curve is achieved by using the hybrid B3LYP functional.