Cross Sections and Swarm Coefficients for H+, H2+, H3+, H, H2, and H− in H2 for Energies from 0.1 eV to 10 keV

Abstract

Graphical and tabulated data and the associated bibliography are presented tor cross sections for elastic, excitation and ionization collisions ofH+, H2 +, H3 +, H, H 2 , and Hwith H2 at laboratory energies from 0.1 to 10 keV. Where appropriate, drift velocities and reaction or excitation coefficients are calculated from the cross sections and recommended for use in analyses of swarm experiments and electrical discharges. In the case ofH+ in H 2 , cross sections for momentum transfer, rotational excitation, vibrational excitation, charge transfer, electronic excitation, and ionization are recommended. Energy-loss or stoppingpower coefficients calculated from these cross sections are much smaller than obtained from stopping-power theory. There are no relevant energy-loss experiments for H+ in H 2. Drift velocity calculations predict runaway for H+ in H2 for electric field to gas density ratiosE/ltgreatcrthan700Td,whcrc 1 Td (townsend) = 10-21 V w".ForH 2 + inH 2 • the cross sections include H3 + formation. charge transfer, vibrational and electronic excitation, and ionization. Drift velocities and average cross sections are calculated for E In> 1 kTd. For H3 + in H 2 • cross sections for momentum transfer. various charge transfer processes, electronic excitation, and ionization and drift velocities are recommended. In the case of H in H 2 • cross sections for momentum transfer, rotational excitation, vibrational excitation, charge transfer, H-formation, electronic excitation, and ionization are recommended. For H2 in H 2 , cross sections for momentum transfer, rotational excitation, vibrational excitation, charge transfer, electronic excitation, and ionization are recommended. In the case ofH-in H 2 , cross sections for momentum transfer, electron detachment, and ionization are recommended and calculated drift velocities are compared ~th experiment. Collisions of electronically excited states with H2 are not included.

New Light Shed on Charge Transfer in FundamentalH++H2Collisions

“…Our total cross section measurements invalidate the previous recommended data [19] for E < 200 eV. This has significant consequences for all forthcoming experiments which would use CT in H þ þ H 2 for normalization purposes.…”

“…This may explain the smaller values they obtained at low energy. The important difference between our measurements and the recommended data of Phelps [19] is a consequence of (i) the difference between our data and those of Ref. [17], which were used to construct the recommended data, and (ii) the emergence of a local maximum in our measurements about E ¼ 45 eV, an energy region previously unexplored experimentally.…”

“…While the total cross sections obtained in all these experiments are practically identical for E > 500 eV, discrepancies at low energies are noticeable. The recommended data of Phelps [19] interpolate between the experimental data of Gealy and Van Zyl [17] for E > 60 eV and those of Holliday et al [20] for E < 5 eV. Differential measurements have been performed by Niedner et al [8] at 30 eV.…”

“…As the energy decreases below 1 keV, this [15]; (blue filled downward triangle) McClure [16]; (blue filled diamond) Gealy and Van Zyl [17]; (blue filled upward triangle) Kusakabe et al [18]. Recommended data: (red dash-dotted line) Phelps [19]. Previous calculations: (green open upward triangle) Baer et al [9]; (green open square) Morales et al [14]; (green dashed line with open downward triangle) Ichihara et al [13]; (green solid line with open circle) Krstić [10]; (green solid line with crosses) Krstić and co-workers [24]; (green dashed line) nonreactive CT from Ref.…”

0D model of magnetized hydrogen–helium wall conditioning plasmas

“…The reaction rates for elastic collisions are obtained via eq. (4), using momentum transfer cross sections from [32,33,34], and implemented in the model according to eq. (5).…”