Models for zero-dimensional molecular magnets

The beauty of molecular magnets lies on their simplicity in what concerns quantum description. Zero-dimensional clusters have, due to the well-known Hamiltonians (e.g., Heisenberg, asymmetric, anti-symmetric and others), analytical solution of the thermodynamic quantities (of course, for a reasonable size of the Hilbert space). The aim of this paper is to describe step-by-step of how to develop models to explain the magnetic behavior of these materials. In spite the possibility of hand calculation (that opens doors for mistakes), computational codes can help to optimize this process of modeling; and then we provide a fully automatize computational routine to do the whole process: the CARDAMOMO package. Nine different Hamiltonians are available, as well as three different methods to obtain the eigenvalues. Thermodynamic quantities are obtained automatically and then fitted to the experimental data. At the end of this paper, an appendix support the physical background behind the Hamiltonians.