Influence of excited molecules on the process of Frictional flow of Nonassociated liquids

Abstract

It is shown that the viscosity of various nonassociated liquids can be described adequately by taking into account both the influence of the rate of the straight-line formation of holes' volume caused by irregular jumpings of excited molecules and the increase in the number of bimolecular collisions which is connected with intramolecular conformational transitions in the liquid phase. The proposed equations allow the calculation of this transport property at different temperatures.

New Semiempirical Equation Describing Evaporation and Condensation in Nonassociated Liquids

“…If we consider the investigated molecules as spherical particles, whose effective radius is proportional to 1/3 ( is the molar volume of a liquid), then the following equation holds for the quantity [4,5]:…”

“…where denotes the surface tension of a liquid, and is a coefficient of proportionality, which is constant for many liquids (i.e., does not depend on ) [4,5]. Then the relative share of the above-mentioned jumping molecules (the first group) can be defined by means of the following equation:…”

“…The second above-mentioned condensation process is the condensation of those vapor molecules, whose one-particle kinetic energy is greater than or equal to the value of (see (5)). This energy is high enough for getting over the potential barrier formed by the molecules vibrating on the surface of the liquid.…”

“…Thinking the evaporating molecules as piercing the surface layer, we deal with the translational motion of a conformationally flexible molecule through the layer of conformationally rigid ones. Hereafter we shall consider that the one-particle potential barrier (see (5)) which must be got over by this molecule is also proportional to the number of its bimolecular collisions with the corresponding molecules of the surface layer. Thus, in order to calculate the barrier adequately, we must take into account the increase in the number of the bimolecular collisions which are caused by the conformational transitions of this evaporating molecule.…”

“…Thus, in order to calculate the barrier adequately, we must take into account the increase in the number of the bimolecular collisions which are caused by the conformational transitions of this evaporating molecule. Bearing in mind the above-mentioned reasons related to the quantitẏdescribing this increase (see (16)), we can rewrite (5) in the following form:…”