Canonical ensemble: Difference between revisions

From SklogWiki
Jump to navigation Jump to search
mNo edit summary
mNo edit summary
Line 15: Line 15:
where:
where:


* <math> \Lambda </math> is the [[de Broglie wavelength]] (depends on the temperature)
* <math> \Lambda </math> is the [[de Broglie thermal wavelength]] (depends on the temperature)


* <math> \beta = \frac{1}{k_B T} </math>, with <math> k_B </math> being the [[Boltzmann constant]]
* <math> \beta = \frac{1}{k_B T} </math>, with <math> k_B </math> being the [[Boltzmann constant]]
Line 28: Line 28:


:<math> A\left(N,V,T \right) = - k_B T \log  Q_{NVT} </math>
:<math> A\left(N,V,T \right) = - k_B T \log  Q_{NVT} </math>
[[Category:Statistical mechanics]]

Revision as of 12:44, 27 February 2007

Variables:

  • Number of Particles,
  • Volume,
  • Temperature,

Partition Function

Classical Partition Function (one-component system) in a three-dimensional space:

Failed to parse (Conversion error. Server ("https://wikimedia.org/api/rest_") reported: "Cannot get mml. Server problem."): {\displaystyle Q_{NVT}={\frac {V^{N}}{N!\Lambda ^{3N}}}\int d(R^{*})^{3N}\exp \left[-\beta U\left(V,(R^{*})^{3N}\right)\right]}

where:

  • Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \Lambda } is the de Broglie thermal wavelength (depends on the temperature)
  • Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \beta = \frac{1}{k_B T} } , with Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle k_B } being the Boltzmann constant
  • Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle U } is the potential energy, which depends on the coordinates of the particles (and on the interaction model)
  • Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \left( R^*\right)^{3N} } represent the 3N position coordinates of the particles (reduced with the system size): i.e. Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle \int d (R^*)^{3N} = 1 }

Free energy and Partition Function

The Helmholtz energy function is related to the canonical partition function via:

Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle A\left(N,V,T \right) = - k_B T \log Q_{NVT} }