NotesFAQContact Us
Search Tips
Peer reviewed Peer reviewed
Direct linkDirect link
ERIC Number: EJ829429
Record Type: Journal
Publication Date: 2007-May
Pages: 10
Abstractor: As Provided
Reference Count: 8
ISSN: ISSN-0143-0807
Free Volume of the Hard Spheres Gas
Shutler, P. M. E.; Martinez, J. C.; Springham, S. V.
European Journal of Physics, v28 n3 p615-624 May 2007
The Enskog factor [chi] plays a central role in the theory of dense gases, quantifying how the finite size of molecules causes many physical quantities, such as the equation of state, the mean free path, and the diffusion coefficient, to deviate from those of an ideal gas. We suggest an intuitive but rigorous derivation of this fact by showing how all these instances of [chi] amount to different ways of looking at the derivative of the free volume with respect to the packing density. We show how to compute the free volume explicitly for finitely many molecules in a finite box and demonstrate excellent agreement between its derivative and mean free paths obtained from computer simulations, where the number of molecules N varies from 1000 down to 2, and where the mean free paths vary from many times the molecular diameter at low density down to a small fraction of the molecular diameter at high density. Since the boundary corrections involved are relatively simple and intuitive this strengthens the link between the teaching of large N theory for real physical systems, and the running of small N simulations in undergraduate physics laboratories. (Contains 6 figures.)
Institute of Physics Publishing. The Public Ledger Building Suite 929, 150 South Independence Mall West, Philadelphia, PA 19106. Tel: 215-627-0880; Fax: 215-627-0879; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Research
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A