Elastic and related transport cross sections for
(H,D,T)+ + Ar |
Introduction
Important notes and updates
Publications
Data tables
Following the general procedures outlined in our previous
papers which provided theoretical differential
and integral elastic and related transport (momentum transfer and
viscosity) cross sections for collisions among various isotopic
combinations of H+,, H, and H2, and He,
tabulated here are similar data for H+ + Ar, D+ + Ar and,
T+ + Ar for
center of mass collisions energies between 0.1 and 100 eV.
In brief, the calculations were performed by solving the radial
Schrodinger equation for each partial wave component on the
ground state singlet
adiabatic electronic eigenenergy curves. This state
is the ground state energy curve of ArH+ which correlate
asymptotically (separated atoms limit) to Ar. The potential
we used as our starting point in the present calculations were calculated
by computational chemistru code NWChem, using RHF-MP2 procedure in the
range of internuclear separations 0.1-50 a.u.
In order to obtain convergence in partial waves (impact parameter)
for low energy elastic scattering, we extended these potential energy
curves to larger distances by fitting them to the dipole polarization
potential (dipole polarizability from Reference 5).
Much as in our previous calculations, the radial integration was
carried out using Johnson's logarithmic derivative method, beginning
the integration at an internuclear separation of 0.1 a.u. and
with a step of 0.0001 a.u., and then matching the solution to plane
waves at 200 a.u. Convergence in partial waves is monitored until
the partial amplitude, al, satisfies
1-Re(al) < 10-6 and Im(al) <
10-6 for 20 consecutive values of l. The elastic differential
cross section is computed at 768 angles between 0 and pi, to facilitate
Gauss-Legendre integration and to assure that all the oscillations of
the differential cross section are represented accurately enough to
assure convergence during this integration. The procedure is
repeated for 31 energies spanning the center of mass collision
energy range of 0.1-100 eV.
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- 1. The data have been posted as of 2/25/01. Any updates will be
documented here.
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The results for collisions among all isotopic combinations of hydrogen
ions, atoms, and molecules are described in the following references
and here.
The data form the basis for a volume of recommended elastic and transport
related cross sections (reference 1), and many details of the calculations,
their physical interpretation, and their inter-relationships are detailed
in references 2-4.
- 1. ``Elastic and related transport cross sections for collisions
among isotopomers of H+ + H, H+ + H2,
H+ + He, H + H, and H + H2'', P.S. Krstic and
D.R. Schultz, Atomic and Plasma-Material Data for Fusion 8,1
(1998). (Postscript file containing the
introduction, basic theoretical description, comparison with existing
results, scaling relations, description of tables and graphs, and
references - approximately 70 pages, 1.68 Mb, approximately 650 pages
of graphs and tables omitted).
- 2. ``Elastic scattering and charge transfer in slow collisions:
Isotopes of H and H+ colliding with isotopes of H and
with He,'' P.S. Krstic and D.R. Schultz, J. Phys. B 32, 3485
(1999). (Postscript (5.48 Mb)).
- 3. ``Consistent definitions for, and relationships among, cross
sections for elastic scattering of hydrogen ions, atoms, and molecules,''
P.S. Krstic and D.R. Schultz, Phys. Rev. A 60, 2118 (1999).
(Postscript (4.21 Mb)).
- 4. ``Elastic and vibrationally inelastic slow collisions:
H + H2, H+ + H2,'' P.S. Krstic and
D.R. Schultz, J. Phys. B 32, 2415 (1999).
(Postscript (3.53 Mb)).
- 5. "Physics of Highly Charged Ions", R.K. Janev, L.P. Presnyakov, and
V.P. Shevelko, Springer-Verlag, New York (1985).
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Integral Cross Sections
The statistically averaged (see explanation above) elastic integral
cross section, momentum transfer cross section, and viscosity cross
section are given in the following table as a function of center of
mass collision energy (from 0.1 to 100 eV). The cross sections are
given in atomic units (i.e. 1 a.u. of cross section =
[Bohr radius]2 = 2.80028 * 10-17 cm2).
The center of mass energies are given by the following formula,
ECM = 10(0.1*n - 1) eV, in order to roughly
uniformly span logarithmically the range of 0.1 to 100 eV.
Differential Cross Sections
The statistically averaged (see explanation above) elastic differential
cross section are given in the files below for 31 center of mass collision
energies from 0.1 to 100 eV. The first column in each files give the
center of mass scattering angle in radians (at 768 values) and the second
column gives the differential cross section multiplied by 2 pi sin(theta)
in atomic units (i.e. 1 a.u. = [Bohr radius]2/srad =
2.80028 * 10-17 cm2/srad). The center of mass
energies are given by the following formula, ECM =
10(0.1*n - 1) eV, in order to roughly uniformly span
logarithmically the range of 0.1 to 100 eV.
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