Equilibrium Thermal Physics of Noble Gases

Abstract

The aim of this research is to apply the author's original computer aided analysis of thermophysical data for pure fluids to noble gases to investigate the unknown aspects in their equilibrium thermal physics. The methodology of the analysis is based on the potential energy density series expansion by the monomer fraction density. To discover the important details and particular features of pair atomic interactions in noble gases, the preprocessed and generalized experimental data have been taken from the US National Institute of Standards and Technology (NIST) online database. In this work the temperature range for analysis of the dimers' bonding parameters is extended as compared to previous author's works due to accounting for the specific temperature dependence of the repulsions' contribution to the potential energy. The found temperature dependences of the pair interaction bond energies signal about the hindered rotation of atoms in dimers near the triple point due to the lack of rotational symmetry of their electronic outer shells. The discovered mutually correlated anomalous temperature dependences of the pair bond energy and the constant volume heat capacity in gaseous Helium require a special investigation of this remarkable phenomenon.

The Physics of Clusters in Real Gases

“…The cluster bond energy E n , defined by Sedunov (2012a) as the cluster dissociation energy, is lower than the depth of the potential well. The ln (W n ) versus β = 1/T plot happens to be linear in the temperature range, where only one isomer dominates, as it was shown by Sedunov (2012aSedunov ( , 2012bSedunov ( , 2013b. This linearity permits to estimate, as the tangent of slope for this part of the graph, the cluster bond energy E n1 in Kelvin, corresponding to the dominating in this range isomer number 1.…”

Clusters—The Seeds of Droplets and Snowflakes

“…If we divide the C u2 by exp(E 2 /T), we find the effective attraction zone volume V 2 for a particle bound with other particle in a dimer. For the Methanol dimers V 2 = 0.82 ml/mol in the range of temperatures 200 -300 K. A small value of V 2 for Methanol, as compared to Noble gases [12], tells about a strong orientation of bonds in dimers, limiting the attraction zone volume in polar gases. Figure 12 shows the V 2 (T) values in a wide range of temperatures.…”

“…The method uses series expansion of precise thermophysical functions by the monomer fraction density [10]. The developed method helps to discover unknown properties of clusters and molecular interactions in molecular [11] and atomic [12] gases and in supercritical fluids [13]- [16]. In this paper we pay attention to polar gases, such as the water and methanol vapors, which at low temperatures possess tetramers with giant bond energies and strong orientation of hydrogen bonds.…”