Role of electron correlations in deoxyribonucleic acid duplexes: is an extended Hubbard Hamiltonian a good model in this case?

The parameters of an extended Hubbard Hamiltonian for poly(dA)-poly(dT) and poly(dG)-poly(dC) homopolynucleotide duplexes in A- and B-deoxyribonucleic acid (DNA) geometries have been estimated within the framework of the Fortunelli-Painelli dimer model using Hartree-Fock semiempirical quantum chemistry reinforced by a configuration interaction scheme to include one- and two-electron excitations. It is tentatively concluded that inclusion of electron correlations is essential in treating DNA duplexes.