On the centre of mass velocity in molecular dynamics simulations

Fuente: Universidad Nacional Autónoma de México

Resumen: Molecular dynamics simulations are performed on a fluid at supercritical conditions to analyze the effect that the velocity of centre of mass (VCOM) of the system has on temperature and phase stability. Standard rescaling velocities and Nose-Hoover chains of thermostats methodś are used to...

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Bibliographic Details
Main Author: Méndez Maldonado, G. A.
Format: Artículo de Investigación
Language:English
Published: Sociedad Mexicana de Física, A.C. 2012
Universidad Nacional Autónoma de México; Facultad de Ciencias
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Summary:Resumen: Molecular dynamics simulations are performed on a fluid at supercritical conditions to analyze the effect that the velocity of centre of mass (VCOM) of the system has on temperature and phase stability. Standard rescaling velocities and Nose-Hoover chains of thermostats methodś are used to carry out simulations on Square Well, Lennard-Jones and Soft Primitive potential models. Removing the VCOM at the beginning or during the simulation is not required for the Nose-Hoover chain of thermostats to keep the correct temperature of the system, however, it́ is fundamental to keep null the VCOM when the traditional rescaling velocity scheme is used. It is shown that if the VCOM is removed only at the beginning of the simulation the internal and external temperatures are not the same for very long simulations and the fluid becomes a solid. The temperatures and physical properties obtained using the Nose-Hoover chain method are the same as those obtained by removinǵ the VCOM during the simulation in the rescaling velocity procedure.