Characteristic Curves of the Lennard-Jones Fluid

Equations of state based on intermolecular potentials are often developed about the Lennard-Jones (LJ) potential. Many of such EOS have been proposed in the past. In this work, 20 LJ EOS were examined regarding their performance on Brown’s characteristic curves and characteristic state points. Brown’s characteristic curves are directly related to the virial coefficients at specific state points, which can be computed exactly from the intermolecular potential. Therefore, also the second and third virial coefficient of the LJ fluid were investigated. This approach allows a comparison of available LJ EOS at extreme conditions. Physically based, empirical, and semi-theoretical LJ EOS were examined. Most investigated LJ EOS exhibit some unphysical artifacts.

Ideal Bose Gas in Some Deformed Types of Thermodynamics. Correspondence between Deformation Parameters

Two approaches to the construction of thermodynamics in the framework of the q- and м-formalisms, which correspond to certain deformations of the algebra of the creation–annihilation operators, have been considered. By comparing the obtained results, an approximate, independent of the space dimension, correspondence was revealed between the second virial coefficients for the ideal q- and м-deformed Bose gases. The corresponding discrepancy arises only at the level of the third virial coefficient. A method for emulating the м-deformed Bose gas up to the third virial coefficient inclusive by means of the two-parametric nonadditive Polychronakos statistics is demonstrated.

Erratum: Improved First-Principles Calculation of the Third Virial Coefficient of Helium

The calculations of C(T) for 3He in the original paper were in error at the lowest temperatures due toan incorrect accounting for the quantum statistics of fermions, as explained in Ref. [2]. A corrected version of Table 6 is given below. The calculations for 4He are not affected by this error.

Equation of State of Four- and Five-Dimensional Hard-Hypersphere Mixtures

New proposals for the equation of state of four- and five-dimensional hard-hypersphere mixtures in terms of the equation of state of the corresponding monocomponent hard-hypersphere fluid are introduced. Such proposals (which are constructed in such a way so as to yield the exact third virial coefficient) extend, on the one hand, recent similar formulations for hard-disk and (three-dimensional) hard-sphere mixtures and, on the other hand, two of our previous proposals also linking the mixture equation of state and the one of the monocomponent fluid but unable to reproduce the exact third virial coefficient. The old and new proposals are tested by comparison with published molecular dynamics and Monte Carlo simulation results and their relative merit is evaluated.

Theoretical study of third virial coefficient with Kihara potential

In this paper, a new formula has been presented for accurate calculation of the third virial coefficient with Kihara potential. The obtained formula allows us to the determination of thermodynamic properties of imperfect gases. The validity of the formula has been tested by application to some gases C2H6, C3H8, C(CH3)4, and n – C5H12. The obtained results have been compared with the other studies. These comparisons show that the formula developed in this study is in good agreement with the data available in the literature.