Model hysteresis dimer molecule I: Equilibrium properties

A Hamiltonian system describing hysteresis behavior in a dimeric chemical reaction is modeled in a MD simulation utilizing novel two-body potentials with switches that is particularly suitable for numerical thermodynamical investigations. It is surmized that such reaction mechanisms could exist in nature on the basis of recent experiments, which indicate that electromagnetic hysteresis behavior is exhibited at the molecular level, although experimental interpretations tend to construct models that avoid such mechanisms. Numerical results of various common equilibrium thermodynamical and kinetic properties are presented together with new algorithms that were implemented to compute these quantities, where no unusual thermodynamics was observed for the chemical reaction which might be interpreted as not being “time reversible invariant” and therefore susceptible to manifesting unusual thermodynamical phenomena, which might contradict any of the known laws of thermodynamics. A revision of the concept of “time reversibility” to accommodate the above results is suggested. The general design of the reaction mechanism also allows for the use of conventional potentials and by the utilization of switches, overcomes the bottleneck of computations which involves multi-body interactions. The initial theoretical, program and algorithm development was done at Norwegian University of Science and Technology-NTNU, Institute of Physical Chemistry, (Trondheim, Norway) during a sabbatical visit 2000–2001 financed by University of Malaya. The method of MD used here conforms to the periodic boundary conditions and thermostatting algorithms developed or refined by Ikeshoji and Hafskjold for standard, non-reacting particles. Their approach is non-synthetic using traditional Verlet integration of Newton’s equations of motion.