Molecular Collision Diameters and Electronic Polarizabilities: Inherent Relationship and Fast Evaluation

Abstract

The collision diameter σ for a large set of molecular species is related to the static electronic polarizability αel. A remarkable correlation between these quantities conceptually similar to the analogous one previously identified for atoms is revealed. Our recommended model is the function σ­(αel) = p 1 + p 2αel 1/3, where p 1 = 0.768 Å and p 2 = 2.168 are the fitting parameters providing the best overall match to the reference data for collision diameter (181 data points). The obtained correlation allows one to easily find the collision diameter of molecules from the known polarizability and vice versa. These findings can be useful for many applications, where there is a need for inexpensive assessments of the collision diameters or electronic polarizabilities, for example, when developing the transport property databases for modeling of chemically reacting flows.

Polarizability in Astrochemical Studies of Complex Carbon-Based Compounds

“…It is the main quantity defining intermolecular interactions (inductive and dispersion interactions, ion mobility, collisions, diffusion in gases, etc.). We do not stop here on these relations, as they have been exhaustively described in classic books and some key papers. − ,− …”

“…Being important for computational models of astrochemistry, the collision diameters (σ) of molecular species correlate with their mean polarizabilities. Loukovitski and Sharipov recommend the following relation that perfectly describes the reference data for collision diameters with fitting parameters p 1 = 0.768 Å and p 2 = 2.168. The obtained correlation allows one to easily find the collision diameter of molecules from the known polarizability and vice versa.…”

“…13 Being important for computational models of astrochemistry, the collision diameters (σ) of molecular species correlate with their mean polarizabilities. Loukovitski and Sharipov 12 recommend the following relation that perfectly describes the reference data for collision diameters…”

Toward size-dependent thermodynamics of nanoparticles from quantum chemical calculations of small atomic clusters: a case study of (B2O3)n

“…14,173 Note that this procedure was validated against the set of available data on the collision cross sections and binary diffusion coefficients and it was shown to predict adequately the collision diameters of a number of diatomic and polyatomic species of general interest. 172,173 The corresponding σ ( n ) data presented in Table 3 further indicate that the gas kinetic size of the largest cluster considered ( n = 8) actually reaches the nanometer range.…”

“…Table 3 lists the symmetry type of established (B 2 O 3 ) n configurations, their multiplicity 2S + 1, atomization energy E at , enthalpy of formation at zero temperature D f H 0 0 , and standard enthalpy of formation D f H 0 298 . In addition, to specify the spatial extent of the particles in question, the collision diameters s of (B 2 O 3 ) n clusters essential for estimating their transport properties and reaction kinetics in the gas phase 14,172 were straightforwardly obtained from their equilibrium structures in compliance with the procedure. 14,173 Note that this procedure was validated against the set of available data on the collision cross sections and binary diffusion coefficients and it was shown to predict adequately the collision diameters of a number of diatomic and polyatomic species of general interest.…”