Isothermal-isobaric ensemble: Difference between revisions

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* V (Volume)
* V (Volume)


The classical partition function, for a one-component atomic system in 3-dimensional space, is given by
The [[classical partition function]], for a one-component atomic system in 3-dimensional space, is given by


<math> Q_{NpT} = \frac{\beta p}{\Lambda^3 N!} \int_{0}^{\infty} d V  V^{N} \exp \left[ - \beta p V \right] \int d ( R^*)^{3N}  \exp \left[ - \beta U \left(V,(R^*)^{3N} \right) \right]
:<math> Q_{NpT} = \frac{\beta p}{\Lambda^3 N!} \int_{0}^{\infty} d V  V^{N} \exp \left[ - \beta p V \right] \int d ( R^*)^{3N}  \exp \left[ - \beta U \left(V,(R^*)^{3N} \right) \right]
</math>
</math>


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*<math> \beta = \frac{1}{k_B T} </math>;  
*<math> \beta = \frac{1}{k_B T} </math>;  


*<math> \Lambda </math> is the '''de Broglie''' wavelength
*<math> \Lambda </math> is the [[de Broglie wavelength]]


*<math> \left( R^* \right)^{3N} </math> represent the reduced position coordinates of the particles; i.e. <math> \int d ( R^*)^{3N}  = 1 </math>
*<math> \left( R^* \right)^{3N} </math> represent the reduced position coordinates of the particles; i.e. <math> \int d ( R^*)^{3N}  = 1 </math>

Revision as of 12:16, 26 February 2007

Variables:

  • N (Number of particles)
  • p (Pressure)
  • T (Temperature)
  • V (Volume)

The classical partition function, for a one-component atomic system in 3-dimensional space, is given by

where

  • ;
  • represent the reduced position coordinates of the particles; i.e.
  • is the potential energy, which is a function of the coordinates (or of the volume and the reduced coordinates)


References

  1. D. Frenkel and B. Smit, "Understanding Molecular Simulation: From Alogrithms to Applications", Academic Press