Total scattering cross sections for intermediate-energy positrons in the molecular gases H₂, O₂, N₂, CO₂and CH₄

Positron scattering from methane

“…1-3 are purely statistical and are at the one standard deviation level. However, representative total errors (in violet at 0.1, 1, and 10 eV) are also plotted in those figures, to enable a better comparison to be made to the current SMC results and the earlier experimental data [4][5][6][7][8] and previous computations [10][11][12][13][14]. The arrows in Figs.…”

“…Given the above, it is thus not surprising that positron scattering from CH 4 has been already relatively well studied. In this regard we note the experimental total cross sections (TCSs) from Charlton et al [4,5], Sueoka and Mori [6], Floeder et al [7], and Dababneh et al [8], and the discrete vibrational excitation integral cross sections from Sullivan et al [9].…”

“…In this regard we note the experimental total cross sections (TCSs) from Charlton et al [4,5], Sueoka and Mori [6], Floeder et al [7], and Dababneh et al [8], and the discrete vibrational excitation integral cross sections from Sullivan et al [9]. From a theoretical perspective, various model calculations from Jain and Thompson [10], Jain [11], Gianturco et al [12], Jain and Gianturco [13], and Baluja and Jain [14] are noted and are of relevance to the present study.…”

“…Indeed one rationale for the present investigation is to try and shed more light on this state of affairs. Another rationale is that none of the available measurements [4][5][6][7][8] extend below an incident positron energy of about 1 eV, whereas it is expected that the effect of the target polarization on the scattering dynamics will become very important at those lower energies [15,16].…”

Scattering of low- to intermediate-energy positrons from molecular hydrogen

“…The experimental measurements of the total cross sections have been made by several groups. In particular, the positron impact energies ranging from 1 to 500 eV are covered by Hoffmann et al [21], from 1.5 to 301 eV by Zhou et al [22], from 14 to 600 eV by Charlton et al [23], from 2.15 to 20.84 eV by Charlton et al [24], and from 8 to 400 eV by Deuring et al [25]. To the best of our knowledge, no other theoretical calculations of total cross sections have been able to predict the stucture in this curve over as large a range of positron energies as in the present calculations.…”