Test volume method: Difference between revisions

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(New page: An alternative to the virial pressure route to calculating the pressure, there is a method which consists on evaluating the change in internal energy, <math>\Delta U</math> produce...)
 
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:<math> p  =  \frac{ k_B T  N}{V} + \frac{ k_B T  }{ \Delta V } \log \langle \exp(-\Delta U/k_B T )\rangle,</math>
:<math> p  =  \frac{ k_B T  N}{V} + \frac{ k_B T  }{ \Delta V } \log \langle \exp(-\Delta U/k_B T )\rangle,</math>
where <math>k_B</math> is the [[Boltzmann constant]] and <math>T</math> is the [[temperature]].
where <math>k_B</math> is the [[Boltzmann constant]] and <math>T</math> is the [[temperature]].
The method is clearly inspired by the [[ Widom test-particle method]] to obtain the [[chemical potential]].
The method is clearly inspired by the [[ Widom test-particle method]] to obtain the [[chemical potential]].
==References==
==References==
#[http://dx.doi.org/10.1063/1.472721  V. I. Harismiadis, J. Vorholz, and A. Z. Panagiotopoulos "Efficient pressure estimation in molecular simulations without evaluating the virial", Journal of Chemical Physics '''105''' p. 8469 ]
#[http://dx.doi.org/10.1063/1.472721  V. I. Harismiadis, J. Vorholz, and A. Z. Panagiotopoulos "Efficient pressure estimation in molecular simulations without evaluating the virial", Journal of Chemical Physics '''105''' pp. 8469- (1996)]

Revision as of 11:56, 7 February 2008

An alternative to the virial pressure route to calculating the pressure, there is a method which consists on evaluating the change in internal energy, produced by a small change in the volume of the system . It can be shown that

where is the Boltzmann constant and is the temperature. The method is clearly inspired by the Widom test-particle method to obtain the chemical potential.

References

  1. V. I. Harismiadis, J. Vorholz, and A. Z. Panagiotopoulos "Efficient pressure estimation in molecular simulations without evaluating the virial", Journal of Chemical Physics 105 pp. 8469- (1996)