Electronic structure and parity effects in correlated nanosystems

We discuss the spectral, transport and magnetic properties of quantum nanowires composed of N\leq 13 atoms and containing either even or odd numbers of valence electrons. In our approach we combine Exact Diagonalization and Ab Initio calculations (EDABI method). The analysis is performed as a function of the interatomic distance. The momentum distribution differs drastically for those obtained for even N with those for odd N, whereas the Drude weight evolves smoothly. A role of boundary conditions is stressed.