  We employ two Tight-Binding (TB) approaches to study the electronic structure
and hole or electron transfer in B-DNA monomer polymers and dimer polymers made
up of $N$ monomers (base pairs): (I) at the base-pair level, using the on-site
energies of base pairs and the hopping integrals between successive base pairs,
i.e., a wire model and (II) at the single-base level, using the on-site
energies of the bases and the hopping integrals between neighboring bases,
i.e., an \textit{extended} ladder model since we also include diagonal
hoppings. We solve a system of $MD$ ("matrix dimension") coupled equations [(I)
$MD$ = $N$, (II) $MD$ = $2N$] for the time-independent problem, and a system of
$MD$ coupled $1^\text{st}$ order differential equations for the time-dependent
problem. We study the HOMO and the LUMO eigenspectra, the occupation
probabilities, the Density of States (DOS) and the HOMO-LUMO gap as well as the
mean over time probabilities to find the carrier at each site [(I) base pair or
(II) base)], the Fourier spectra, which reflect the frequency content of charge
transfer (CT) and the pure mean transfer rates from a certain site to another.
The two TB approaches give coherent, complementary aspects of electronic
properties and charge transfer in B-DNA monomer polymers and dimer polymers.
