ICS-2 Seminar: Maintaining the equipartition theorem in small heterogeneous molecular dynamics ensembles
Nima H. Siboni
Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf
- 26.09.2013 11:00 Uhr
- Seminarraum 2001, Geb. 04.16
The equipartition theorem, as one of the fundamental theorems of the equilibrium statistical physics, served as a tool to measure and control the temperature in computer simulations. Its application has been extended even to non-equilibrium cases, where the temperature is not a well-defined quantity [1,2]. But it has been reported recently that the equipartition theorem is violated in molecular dynamics simulations with periodic boundary condition . This effect is associated with the conservation of the total momentum. I will talk about our fluctuating center of mass molecular dynamics approach to solve this problem . Using the analogy to a system exchanging momentum with its surroundings, we work out—and validate via simulations—an expression for the rate at which fluctuations shall be added to the system. It is shown that the proposed method maintains equipartition both at equilibrium and beyond equilibrium in the linear response regime.
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 R. B. Shirts, S. R. Burt, A. M. Johnson, Periodic boundary condition induced breakdown of the equipartition principle and other kinetic effects of finite sample size in classical hard-sphere molecular dynamics simulation, J. Chem. Phys., 125 164102 (2006)
 N. H. Siboni, D. Raabe, and F. Varnik, Maintaining the equipartition theorem in small heterogeneous molecular dynamics ensembles, Phys. Rev. E 87, 030101(R) (2013).
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