Contribution of Bound, Metastable, and Free Molecules to the Second Virial Coefficient and Some Properties of Double Molecules

Abstract

The second virial coefficient for molecules interacting with a spherically symmetric potential is divided into three parts: (1) a contribution Bb, related to the equilibrium constant for the formation of bound double molecules; (2) a contribution Bm, related to the equilibrium constant for the formation of metastably-bound double molecules; and (3) a contribution Bf, due to molecules which interact but are free to separate after the interaction. Equations are given for determining each of the three parts of the second virial coefficient. A detailed treatment of these three contributions together with numerical tables on a reduced temperature basis is given for the square-well, Sutherland, and Lennard-Jones (6–12) potentials. The mean lifetimes of metastably bound double molecules are discussed, and numerical values are given for the special case of argon. Tables for computing mean lifetimes in other Lennard-Jones gases are given. It is found that most metastably bound double molecules have mean lifetimes considerably longer than the mean time between collisions at ordinary pressures. Finally, an equation is developed for the number of vibrational levels of a double molecule.

Dimerization Degree of Water Molecules, Their Effective Polarizability, and Heat Capacity of Saturated Water Vapor

“…Автори використовують рiзнi методи для дослiдження: 1) визначення концентрацiї ди-мерiв d за допомогою другого вiрiального коефiцi-єнта [10][11][12]; 2) прямий розрахунок [13][14][15], що ви-магає знання коливальних i обертальних спектрiв збуджень димерiв; 3) визначення концентрацiї за допомогою дослiдження теплопровiдностi водяної пари. На жаль, результати суттєво вiдрiзняються один вiд одного.…”

Ninth Conference on Thermal Conductivity, Iowa State University, Ames, Iowa, October 6--8, 1969.

“…The heat transfer by radiation in a pardy transparent liquid disc capable of emitting and absorbing radiation has been calculated for steady state conditions by Fritz and Poltz (40). The disc is linnited by two infinite, isothermal, parallel plates which emit, absorb and reflect thermal radiation.…”

“…The bases of the molecular association have been described by Hirschfelder (39), Stogryn and Hirschfelder (40) have made calculation for the thermal conductivity ; they consider monomer-dimer collisions but limit their definition of dimers to bound and metastable pairs. They use an expansion in the pressure rather than the density and they determine the coerficient p = [A"'/AAn ^ wP'Jp=0…”

Thermochemistry and Kinetics of Evaporation and Condensation for Small Water Clusters

“…There have been several suggestions of cluster definitions in the literature, which limit the contribution from dissociative states to finite values. The use of centrifugal potentials to define the regions of phase space revelant to dimer formation for structureless monomers goes back to the pioneering work of Hill [51] and Stogryn and Hirshfelder [52] and has been extended to water dimers [22]. The definition of a cluster has long been recognized as an important issue in molecular approaches of vapor-to-liquid homogeneous nucleation, because clusters that contribute to nucleation are inherently unstable [53][54][55][56][57][58][59][60][61][62][63].…”