ELECTRONIC AND MAGNETIC-STRUCTURE OF MNF2 AND NIF2

We present an ab initio study of the electronic and magnetic structure of the antiferromagnetic state of MnF2 and NiF2. From the band structures of these two compounds we derive densities of states (DOS), electron densities, spin densities, electric-field gradients, and total energies. We use a simple molecular-orbital scheme to interpret the results. The internal coordinate u is determined by total-energy minimization for MnF2 and agrees well with experiment as well as with the calculated electric-field gradients or the electron densities. Recent spin-dependent x-ray-absorption spectra are interpreted in terms of partial DOS of the unoccupied Mn 4p states.