Classical fluids of negative heat capacity
- Univ. of Southampton (United Kingdom)
- Univ. of Florida, Gainesville, FL (United States)
It is shown that new parameters X can be defined such that the heat capacity C[sub x] [identical to] T([partial derivative]S/[partial derivative]T)[sub x] is negative, even when the canonical ensemble [i.e., at fixed T = ([partial derivative]U/[partial derivative]S)[sub y] and Y [ne] X] is stable. This implies an extension of the classical theory of polytropes from ideal gases to general fluids. As examples of negative heat capacity systems the authors treat blackbody radiation and general gas systems with nonsingular [kappa][sub T]. for the case of a simple ideal gas we even exhibit an apparatus which enforces a constraint X(p,V) = const that makes C[sub x]<0. It is shown that it is possible to infer the statistical mechanics of canonically unstable systems-for which even the traditional heat capacities are negative-by imposing constraints that stabilized the associated noncanonical ensembles. Two explicit models are discussed. 11 refs., 2 figs.
- DOE Contract Number:
- FG05-86ER40272
- OSTI ID:
- 7281146
- Journal Information:
- Journal of Statistical Physics; (United States), Vol. 73:1-2; ISSN 0022-4715
- Country of Publication:
- United States
- Language:
- English
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