  For reliable and efficient inclusion of electron-electron correlation effects
in nanosystems we propose a combined density-functional-theory/nonhomogeneous
dynamical-mean-field-theory (DFT + DMFT) approach which employs an approximate
Iterative Perturbative Theory (IPT) impurity solver. The validity of the method
is demonstrated by successful examination of the size-dependent magnetic
properties of iron nanoparticles containing 11-100 atoms. We show that the DFT+
DMFT solution is in very good agreement with experimental data, in particular
it does not lead to the overestimation of magnetization that is found with the
DFT and DFT+U techniques. More importantly, we demonstrate that DFT+DMFT
approach can be used for accurate and realistic description of nanosystems
containing about hundred atoms.
