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Study of Equilibrium Critical Phenomena in Fluid Argon


Wu, Shyue Yuan (1972) Study of Equilibrium Critical Phenomena in Fluid Argon. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/Z20H-HM70.


The refractive index of fluid argon was measured by using the method of angle of minimum deviation for λNa = 5893Å. The measurements were carried out along the coexistence curve and along fourteen single phase isotherms from 150.7° to 163°K at pressures from 40 to 90 atmospheres.

The Lorentz-Lorenz relation was used to relate the refractive index data to the densities and subsequently to find the isothermal compressibilities along the singla phase isotherms. Following the law of rectilinear diameter and the simple power laws for critical exponents, the values of the critical temperature and exponents for argon were found to be Tc = 150.725° ± 0.010°K, β = 0.3574 ± 0.0027, and γ = 1.170 ± 0.013. Also values of nc = 1.08611 and Pc = 47.983 atm were determined. These values agree well with others reported for argon. Comparison of the values of β and γ with those predicted by the classical theory and the three-dimensional lattice gas model suggests that the latter gives a better description of the critical behavior of fluid argon.

Analysis of the reduced chemical potential differences, computed from the refractive index data along the singla phase isotherms, has been made by using the scaled equation of state first proposed by Widom. Reasonable values Tc and γ were obtained when the value of β determined above was used.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Chemical Engineering
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Pings, Cornelius J.
Thesis Committee:
  • Unknown, Unknown
Defense Date:7 December 1971
Funding AgencyGrant Number
Air Force Office of Scientific ResearchUNSPECIFIED
Shell Companies FoundationUNSPECIFIED
Record Number:CaltechTHESIS:11212017-114310188
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:10567
Deposited By: Benjamin Perez
Deposited On:22 Nov 2017 15:37
Last Modified:02 Dec 2020 01:03

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