Institute of Physics, Academy of Sciences, Prag.
Application of the dynamical mean-field theory (DMFT) to multi-band models obtained with ab initio bandstructure methods has lead to better qualitative and quantitative understanding of correlated-electron materials. However, mostly one-particle or local quantities were studied within this approach so far. We will present an efficient numerical method for calculation of the non-local two-particle response functions. Computations of this type can be used to search for divergencies, which identify instabilities towards long-range ordering. Applications to benchmark cases such as single-band and two-band Hubbard model as well as a 'sharp' attempt to describe the Verwey transition in magnetite will be presented.