Eigen energies and the statistical distributions of the rovibrational levels of the bosonic van der Waals argon trimer

Thermodynamic Properties of van der Waals Dimers and Trimers of Nonpolar Gases and Their Correlation with Lennard-Jones Potential Well Depths

A method of unifying the equilibrium thermodynamic properties ΔH^o and ΔG^o relating to the van der Waals dimers and trimers of 15 nonpolar gases (He-Xe, H₂, D₂, CH₄, CF₄, ethene, ethane, CO₂, SF₆, propane, and neopentane) is described. Values of ΔH^o and ΔG^o, obtained at the reduced temperature T_r = 0.7, show good correlation with the respective Lennard-Jones pair potential well depth, calculated from the monomer critical temperature and the acentric factor. Such relationships present the opportunity to estimate the van der Waals dimer and trimer thermodynamic properties of other nonpolar molecules, and examples of seven such applications are given. It is found that the enthalpies of dimerization and trimerization of the 15 gases are about 21 and 29% of the respective condensation enthalpies, providing information about the thermodynamics of small clusters in relation to liquefaction.

Statistical properties of the rovibrational bound levels for Ar2Kr

We calculate the rovibrational bound levels with total angular momentum J = 0, 1 of ⁴⁰Ar₂⁸⁴Kr trimer using the slow variable discretization method combined with the finite-element method-discrete variable representation basis. The statistical distributions of the rovibrational levels for J^Π=0^e, 1^e, and 1^o symmetries are presented and the effects of the Axilrod-Teller potential term are considered. For the 0^e and 1^e symmetries, the Axilrod-Teller term makes the spectra become fully chaotic. However, for the 1^o symmetry, statistical properties depend mainly on the coupling between K = 0 and K = 1 and the Axilrod-Teller term has a small effect.