Properties of a correlated nanoscopic chain close to the metal-insulator transition

We review our recent results concerning the electronic properties of a nanoscopic system with inclusion of long-range Coulomb interactions that are obtained by combining exact diagonalization in the Fock space with an ab initio method (EDABI). The system evolution is discussed as a function of lattice parameter R. A transformation from a nanometal to localized spin system is observed. With the help of a finite-size scaling we determine the discontinuity of the momentum distribution at the Fermi points. Our results imply Fermi-liquid-like behavior for R less than or similar to 3a(0) (a(0) is the Bohr radius). The quasiparticle mass is almost divergent at the localization threshold, where the particle distribution of the Fermi-Dirac type gets smeared out. The charge-gap evolution is compared with that of the Slater gap. Also, the single-particle spectral function and the corresponding density of states are presented. The analysis is performed using 1s-like Gaussian-type STO-3G basis.