In this paper, we calculate the second virial coefficient for binary mixtures of Ar with CH4 and CO in order to evaluate the performance of equations of state (EOSs). The investigated EOSs are van der Waals (vdW), Redlich-Kwong (RK), Peng-Robinson (PR), Carnahan-Starling–van der Waals (CS-vdW) and Guggenheim-van der Waals (G-vdW) based on van der Waals model. In our work, we also use Dieterici ...

We evaluate the virial coefficients Bk for k ≤ 10 for hard spheres in dimensions D = 2, · · · , 8. Virial coefficients with k even are found to be negative when D ≥ 5. This provides strong evidence that the leading singularity for the virial series lies away from the positive real axis when D ≥ 5. Further analysis provides evidence that negative virial coefficients will be seen for some k > 10 ...

An interaction potential at different orientation for the CH4 and CO2 complex was derived at theB3LYP level of theory and 6-31+G* basis sets. The potential energy surface was computed on somemolecular geometries. The complete basis set limit of the interaction energies were fitted to wellknownanalytical functions. To determine the second virial coefficients B, U(r) is used to obtain themodel’s ...

Important progress has been made in recent years toward developing a molecular-level understanding of protein phase behavior in terms of the osmotic second virial coefficient, a thermodynamic parameter that characterizes pairwise protein interactions. Yet there has been little practical application of this knowledge to the field of protein crystallization, largely because of the difficult and t...

The available virial coefficients for the two-dimensional hard-disks model are transformed into a matrix representation of the thermodynamic potentials, which allows for an accurate description of the whole fluid phase, up to the phase transition. We find that the fluid phase terminates at the transition point, implying a second-order phase transition in accordance with the Kosterlitz-Thouless-...

Using the Gaussian 2003 software and MP2/ 6–311 ++ G** method for He: He, Ne:Ne andMP2/6-31G method for Ar: Ar, Kr: Kr and HF/STO-3G method for Xe: Xe, the optimizedinteraction energies between two like atoms of rare gases (He, Ne, Ar, Kr and Xe) as a functionof the distances between the centers of two considered atoms were evaluated and the resultswere interpreted according to the Lennard – Jo...

Using the Gaussian 2003 software and MP2 /6 – 311+ G method for the C2H4 : O2, CO:Cl2 andCO2:CO2 pairs and MP2/6-311++G** method for the CO2:H2O pair and B3lyp/6-31G methodfor the O2:O2 pair the optimized interaction energies between two considered pair molecules ofstudied gases(C2H4:O2, CO:Cl2, CO2:H2O, O2:O2 and CO2:CO2 pairs) as a function of thedistances between the centers of two considere...