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 [[ | [[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
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
where is a two-body central potential, is the excess internal energy per particle, and is the radial distribution function.