Cooling a Molecular Chain with a Charge

Based on the Holstein Hamiltonian, the charge dynamics in a chain of sites is investigated at finite temperatures. Previously, we compared results obtained for canonical ensemble and for microcanonical description. According to the simulation results, the transition from the polaron mode to the delocalized state occurs in the same range of thermal energy values of a chain of $$N$$ sites with the adjustment: for the microcanonical description the temperature does not correspond to the initially set one, but is determined after long-term calculations from the average kinetic energy of the chain. In this paper, mixed model is considered: first, a polaron is automatically formed in a short chain with Langevin thermostat. Then, the chain is extended by sites with the same temperature. Dynamics of this system in the microcanonical approach, i.e. for a chain in a vacuum, leads to polaron desruption and cooling of the chain. Such effect may be useful in the design of a molecular DNA refrigerator.