Merged beam measurements of the mutual neutralization of He⁺/H^-and Li⁺/D^-ions

Abstract

Mutual neutralization cross sections for He+/H- and Li+/D- have been measured by a merged beam technique for centre of mass energies between 0.6 and 300 eV. The results are in good agreement with previous inclined and merged beam measurements and with recent theory, all of which only covered energy ranges above 30 eV. At interaction speeds greater than about 3*105 m s-1 results for H+/H-, He+/H-, Li+/H- and Li+/D- all converge.

Inelastic H+Li and H-+Li+collisions and non-LTE Li I line formation in stellar atmospheres

“…This process has a remarkably large cross section near the threshold in alkali-hydrogen systems, particularly to and from the first excited s state. This has been predicted theoretically (Bates & Boyd 1956;Janev & Radulović 1978;Croft et al 1999a;Dickinson et al 1999) and is consistent with experiment (Peart & Hayton 1994). Despite that this process has been known to be remarkably efficient in various fields (e.g.…”

Coulomb trajectory effects on electron-impact detachment of negative ions and on mutual neutralization cross sections

“…However, the effect of attractive Coulomb force indeed is to raise the neutralization cross sections at low energies. Peart and Hayton (1994). The full curve is from the present calculation carried out at E = 0.375 keV folded with effect from the Coulomb trajectory.…”

$ M$-strongly convex subsets and their generating sets

“…In figure 8 the total cross section of the one-electron charge exchange (A) is shown for comparison with Ermolaev's theoretical results [12] and with the results of experimental measurements [2,13,15,16]. The first main difference between that of Ermolaev and our calculation is that the first one treats the H − + He + system as a one-electron system while ours considers it as a three-electron system with allowance for the formation of He in triplet and singlet states.…”

“…For the collisional system H − + He ++ the one-electron charge exchange was studied in [8], and the transfer ionization with formation of He + + H + + e was investigated in [9] and analysed in [10]. The theory of the Li + (1s 2 ) + H − = Li(1s 2 , nl) + H(1s) reaction was considered in [11,12] and its measurements in [13,14].…”

“…In this paper we investigate the cross section of the reaction H − + He + (1s) = H(1s) + He * (1s, nlm) (A) which was previously measured in [2,13,[15][16][17] and calculated in [12,17]. In the present work, the system H − + He + is treated as a three-electron system and the matrix elements for the population of the He * (1s, nlm) singlet and triplet states are derived.…”