A systematic study of carrier transfer along DNA dimers, trimers and polymers including poly(dG)-poly(dC), poly(dA)-poly(dT), GCGCGC..., ATATAT... is presented allowing to determine the spatiotemporal evolution of electrons or holes along a N base-pair DNA segment. Physical quantities are defined including maximum transfer percentage p and pure maximum transfer rate p/T when a period T is defined; pure mean transfer rate k and speed u=kd, where d is the charge transfer distance. The inverse decay length β for the exponential fit k=k0exp(-βd) and the exponent η for the power-law fit k=k0′N-η are computed. β≈0.2-2 Å-1, k0 is usually 10-2-10-1 PHz, generally ≈10-4-10 PHz. η≈1.7-17, k0′ is usually 10-2-10-1 PHz, generally ≈10-4-10 3 PHz. The results are compared with theoretical and experimental works. This method allows to assess the extent at which a specific DNA segment can serve for charge transfer.

Magnetic properties of Ga1−xMnxN are studied theoretically by employing a tight binding approach to determine exchange integrals Jij characterizing the coupling between Mn spin pairs located at distances Rij up to the 16th cation coordination sphere in zinc-blende GaN. It is shown that for a set of experimentally determined input parameters there are no itinerant carriers and the coupling between localized Mn3+ spins in GaN proceeds via superexchange that is ferromagnetic for all explored Rij values. Extensive Monte Carlo simulations serve to evaluate the magnitudes of Curie temperature TC by the cumulant crossing method. The theoretical values of TC(x) are in quantitative agreement with the experimental data that are available for Ga1−xMnxN with randomly distributed Mn3+ ions with the concentrations 0.01 ≤ x ≤ 0.1.

A non conventional source or receiver of THz and above THz electromagnetic radiation is proposed. Specifically, electron or hole oscillations in DNA dimers (two interacting DNA base‐pairs or monomers) are predicted, with frequency in the range f ~ 0.25 - 100 THz (period T ~ 10 - 4000 fs) i.e. potentially absorbing or emitting electromagnetic radiation mainly in the mid‐ and far‐infrared with wavelengths ~ 3 - 1200 μm. The efficiency of charge transfer between the two monomers which make up the dimer is described with the maximum transfer percentage p  and the pure maximum transfer rate pf. For dimers made of identical monomers p = 1, but for dimers made of different monomers p < 1. The investigation is extended to DNA trimers (three interacting DNA base‐pairs or monomers). For trimers made of identical monomers the carrier oscillates periodically with f ~ 0.5 - 33 THz (T ~ 30 - 2000 fs); for 0 times crosswise purines p = 1, for 1 or 2 times crosswise purines p < 1. For trimers made of different monomers the carrier movement may be non periodic. Generally, increasing the number of monomers above three, the system becomes more complex and periodicity is lost; even for the simplest tetramer the carrier movement is not periodic.