Korochkova T. Physical models for the origination of nanoparticle directed motion in low-dimensional systems

The thesis is devoted to the theoretical research on different molecular motor models with the aim to reveal the factors and mechanisms influencing the conversion of different forms of energy into mechanical energy of near-surface nanoparticle motion. It is shown that an orientationally structured adsorbate layer gives rise to an asymmetric electric field which is necessary to produce a molecular motor generating directed particle currents along the surface. The model of a molecular motor with the flashing saw-tooth potential has been considered, and its basic characteristics, viz., the directed particle current and the energy conversion efficiency, have been found in an analytical form. Within the framework of nonequilibrium thermodynamics, the molecular motor efficiency has been analyzed as a function of the coupling degree between two processes, one supplying the energy to the device, and the other withdrawing it. Factors governing the energy conversion efficiency have been analyzed and on this basis a molecular motor model with half-period-shifted potentials has been suggested, its efficiency tending to unity at certain conditions. In this model, exact analytical representations have been found for the particle current generated by the motor and for the motor efficiency in the case that the potential profile contains arbitrarily shaped repetitive elements and changes by jumps. A modification of the transfer-matrix method has been developed in order to calculate the basic characteristics of the motor with periodic continuous arbitrarily shaped potentials; as a result, numerical simulation of mass transfer processes in real systems becomes possible.