Potential curves companions and the forecast of critical parameters

Abstract

Here, new results obtained by modeling intermolecular interactions are presented. A third special point, the inflection point, is introduced in the potential curve (PC) description. General relations are obtained that refer to the coordinates of the minimum and inflection by the PC – and the indices n and m, that determine the shape of individual contributions to Mie potentials (n-m). The new approach applies to 10 globule molecules in the analysis of potentials restored from data on the properties of substances (second virial coefficient and viscosity) using standard methods. The analysis revealed several problems, the source of which turned out to be data characteristics for WF6 molecules. As a result, a new concept has been introduced of PC – companions, which characterize each object. Calculations of the coordinates of the inflection points of PC companions and their comparison with critical parameters showed that one of them (PC with a large value of n) better predicts the critical temperature, and the other (PC with a lower value of n) predicts a critical volume. The results obtained, of fundamental interest, raise new questions.