Energy equation: Difference between revisions

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The '''energy equation''' is given by  
The '''energy equation''' is given, in [[classical thermodynamics]], by  
 
:<math>\left. \frac{\partial U}{\partial V} \right\vert_T  = T \left. \frac{\partial p}{\partial T} \right\vert_V -p  </math>
 
and in [[statistical mechanics]] it is obtained via the [[thermodynamic relations | thermodynamic relation]]
 
:<math>U = \frac{\partial (A/T)}{\partial (1/T)}</math>
 
and making use of the [[Helmholtz energy function]] and the canonical [[partition function]] one arrives at
 
:<math>\frac{U^{\rm ex}}{N}= \frac{\rho}{2} \int_0^{\infty} \Phi(r)~{\rm g}(r)~4 \pi r^2~{\rm d}r</math>
:<math>\frac{U^{\rm ex}}{N}= \frac{\rho}{2} \int_0^{\infty} \Phi(r)~{\rm g}(r)~4 \pi r^2~{\rm d}r</math>
where <math>\Phi(r)</math> is a ''central'' potential, <math>U^{\rm ex}</math> is the  
where <math>\Phi(r)</math> is a ''two-body central'' potential, <math>U^{\rm ex}</math> is the  
[[excess internal energy]] per particle,  and <math>{\rm g}(r)</math> is the [[pair distribution function]].
[[excess internal energy]] per particle,  and <math>{\rm g}(r)</math> is the [[radial distribution function]].
[[category:statistical mechanics]]
[[category:statistical mechanics]]
[[category: classical thermodynamics]]

Latest revision as of 13:31, 29 June 2007

The energy equation is given, in classical thermodynamics, by

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. \frac{\partial U}{\partial V} \right\vert_T = T \left. \frac{\partial p}{\partial T} \right\vert_V -p }

and in statistical mechanics it is obtained via the thermodynamic relation

and making use of the Helmholtz energy function and the canonical partition function one arrives at

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 \frac{U^{\rm ex}}{N}= \frac{\rho}{2} \int_0^{\infty} \Phi(r)~{\rm g}(r)~4 \pi r^2~{\rm d}r}

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 \Phi(r)} is a two-body central potential, 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^{\rm ex}} is the excess internal energy per particle, and 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 {\rm g}(r)} is the radial distribution function.