  We summarize briefly the main results obtained within the proposed EDABI
method combining Exact Diagonalization of (parametrized) many-particle
Hamiltonian with Ab Initio self-adjustment of the single-particle wave function
in the correlated state of interacting electrons. The properties of nanoscopic
chains and rings are discussed as a function of their interatomic distance R
and compared with those obtained by Bethe ansatz for infinite Hubbard chain.
The concepts of renormalized orbitals, distribution function in momentum space,
and of Hubbard splitting as applied to nanoscopic systems are emphasized.
