High-resolution electron impact excitation functions of metastable states of neon, argon, krypton and xenon

Absolute angle-differential cross sections for electron-impact excitation of neon atoms from threshold to 19.5 eV

“…Figure 2 shows that the former three resonances cause strong peaks in the cross sections for the three 3 P levels and window-type features in the excitation function for the 1 P level, in contrast to the latter resonance. These resonances are also prominent in the previous measurements of the total yield for production of metastable Ne (2p 5 3s) 3 P 2,0 atoms [5][6][7]. Theory and experiment agree remarkably well on the shapes, widths and energies of these narrow resonant features, as illustrated in figures 1 and 2.…”

“…Most of the prominent anion resonances in this range [2,[5][6][7] have been resolved. Previous angle-differential work on Ne (2p 5 3s) excitation was carried out at a few discrete impact energies 20 eV.…”

“…A particular point of interest is the coupling of the various anion resonances to specific final states. Apart from numerous work on He (see, e.g., [5,8,9]) and some results for Ar [5,6] and Kr [5,10], such data are currently missing in the literature. …”

Absolute angle-differential cross sections for electron-impact excitation of neon within the first 3.5 eV above threshold

“…This allows for an accurate target description with relatively small configuration expansions. Excellent agreement was observed, for instance, between the calculated energy-dependent cross sections for the production of metastable Ne [2] and Ar [3] atoms with those measured in high-resolution experiments [5][6][7]. For Ne, a very sharp resonance (energy 18.527 meV, width 0.8 meV) was theoretically predicted [2] and subsequently confirmed experimentally [7].…”

Investigation of spin-orbit effects in the excitation of noble gases by spin-polarized electrons

“…It has been suggested that the sudden decrease in linear polarization q3 near threshold for the 3 3~ to 2 3~ transition in helium may be due to the presence of a variety of negative-ion resonances that strongly affect the population of the excited state [32]. Since q 3 for all the J = 3 states and the J = 2 state in krypton has no structure near threshold even in the presence of what are, in general, strong resonances [33], it would appear that the resonances do not decay into either state. If resonances were to have an effect similar to that in helium, then we would expect that there would be a more dramatic decrease in polarization than we observe even with the present energy resolution, since we have previously observed the sudden, large decrease in 773 for the 3 3~-2 3~ transition in helium [34].…”