Hints for the control of magnetic anisotropy in molecular materials

We resume here a fundamental aspect concerning magnetic anisotropy and show with some examples how it is possible to rationalize it. The results are obtained within the framework of a simple angular overlap approach. The application of this model to idealized systems, real monomer molecules, and clusters behaving as single-molecule magnets is described, showing how even within a simple ligand field approach it is possible to get some clues on how to control the magnetic anisotropy, Finally, we focus our analysis on the calculation of fourth-order anisotropy, which has been shown to be of fundamental importance in determining the quantum tunneling effects in single-molecule magnets.