17-03-2014, 10:38 AM
Abstract—A new interaction potential energy surface for
the F2 dimer has recently derived from the quantummechanical
ab initio calculations and described with a
suitable analytical representation. In this work, our previous
results of interaction potential energy surface for the F2
dimer has been used in the framework of the quantumstatistical
mechanics and of the corresponding kinetic theory
to calculate the most important thermophysical properties of
fluorine including second virial coefficient and differential
scattering cross section; the theoretical results are compared
with available experimental data. The transport collision
integrals for F2- F2 interaction are computed and tabulated;
the results yield zero density transport coefficients that
compare well with available measured data. Calculations
have been done up to the first quantum correction for
second virial coefficient and the second-order kinetic theory
approximation for transport coefficients. The Mason-
Monchick approximation (MMA) has been used for the
calculation of collision integrals. Since fluorine is a highly
reactive material, and because of its corrosive nature, there
are limited experimental measurements for its molecular and
bulk properties.
Keywords- collision integrals; diffusion; fluorine;
second virial coefficient; viscosity.
I. INTRODUCTION
Diatomic fluorine molecule F2, is a highly chemically
reactive material, and because of its corrosive nature, there
are limited experimental measurements for its molecular
properties [1]. Molecular fluorine is one of the weakest
covalently bound species and the existence of an accurate
knowledge of intermolecular pair potential will be helpful in
both experimental and theoretical studies. For this reason,
we have recently obtained a detailed anisotropic F2-F2
potential energy surface (PES) from ab initio calculations
using a newly developed aug-cc-pVTZ basis set
supplemented with bond functions at the MP4 level of
theory, and this surface has been represented analytically
[2]. It has been predicted that this PES might be relatively
near the exact one, since the oscillatory behavior of the MP
series up to second order results to an underestimation of the
interaction energy, which can be compensated by the
incompleteness error of the basis set employed.
In this paper, the new F2– F2 intermolecular potential
model has been used in the framework of the quantumstatistical
mechanics and of the corresponding kinetic theory
to calculate the most important thermophysical properties of
F2 governed by two-body and three-body interactions.
Among various macroscopic properties, second virial and
transport coefficients usually are appropriate candidates.
The Wigner-Kirkwood expansion in ?2 is suitable for the
computation of the second virial coefficient. In particular,
Pack [3] developed a formalism for the first-order quantum
correction in ?2 . To calculate the viscosity and diffusion
coefficients, we have used the procedure known as the
Mason-Monchick Approximation (MMA) [4], which is the
classical counterpart of the infinite-order-sudden (IOS)
approximation of quantal inelastic scattering.
the F2 dimer has recently derived from the quantummechanical
ab initio calculations and described with a
suitable analytical representation. In this work, our previous
results of interaction potential energy surface for the F2
dimer has been used in the framework of the quantumstatistical
mechanics and of the corresponding kinetic theory
to calculate the most important thermophysical properties of
fluorine including second virial coefficient and differential
scattering cross section; the theoretical results are compared
with available experimental data. The transport collision
integrals for F2- F2 interaction are computed and tabulated;
the results yield zero density transport coefficients that
compare well with available measured data. Calculations
have been done up to the first quantum correction for
second virial coefficient and the second-order kinetic theory
approximation for transport coefficients. The Mason-
Monchick approximation (MMA) has been used for the
calculation of collision integrals. Since fluorine is a highly
reactive material, and because of its corrosive nature, there
are limited experimental measurements for its molecular and
bulk properties.
Keywords- collision integrals; diffusion; fluorine;
second virial coefficient; viscosity.
I. INTRODUCTION
Diatomic fluorine molecule F2, is a highly chemically
reactive material, and because of its corrosive nature, there
are limited experimental measurements for its molecular
properties [1]. Molecular fluorine is one of the weakest
covalently bound species and the existence of an accurate
knowledge of intermolecular pair potential will be helpful in
both experimental and theoretical studies. For this reason,
we have recently obtained a detailed anisotropic F2-F2
potential energy surface (PES) from ab initio calculations
using a newly developed aug-cc-pVTZ basis set
supplemented with bond functions at the MP4 level of
theory, and this surface has been represented analytically
[2]. It has been predicted that this PES might be relatively
near the exact one, since the oscillatory behavior of the MP
series up to second order results to an underestimation of the
interaction energy, which can be compensated by the
incompleteness error of the basis set employed.
In this paper, the new F2– F2 intermolecular potential
model has been used in the framework of the quantumstatistical
mechanics and of the corresponding kinetic theory
to calculate the most important thermophysical properties of
F2 governed by two-body and three-body interactions.
Among various macroscopic properties, second virial and
transport coefficients usually are appropriate candidates.
The Wigner-Kirkwood expansion in ?2 is suitable for the
computation of the second virial coefficient. In particular,
Pack [3] developed a formalism for the first-order quantum
correction in ?2 . To calculate the viscosity and diffusion
coefficients, we have used the procedure known as the
Mason-Monchick Approximation (MMA) [4], which is the
classical counterpart of the infinite-order-sudden (IOS)
approximation of quantal inelastic scattering.