Approximate density-functional calculations of spin densities in large molecular systems and complex solids

We have extended an approximate density-functional based method to the calc ulation of spin densities and subsequently to electron paramagnetic hyperfi ne interactions. The isotropic hyperfine coupling constants of protons in m olecules are calculated in quantitative agreement with experimental results and ab initio data. Qualitative agreement compared to ab initio data has a lso been found for other atoms in molecules and solid state systems.