First-principles calculations were made of the electronic ground-state properties of tetrahedral Mn4 clusters. On the basis of total energy calculations, it was shown that a cluster of 4 substitutional Mn atoms was unlikely. Instead, 2 different cluster models which involved 4 interstitial Mn atoms, both of which had a high-spin S = 12/2 ground state, were considered. It was not found to be possible to predict which cluster was the more likely on the basis of the total energies. Upon comparing calculated and experimental hyperfine interactions, a cluster model was favored in which four Mn atoms on interstitial sites were centered around another interstitial site.

H.Overhof: Materials Science Forum, 1995, 196-201, 1363-8