Temperature dependence of binary and ternary recombination of D3+ ions with electrons

Abstract

Flowing and stationary afterglow experiments were performed to study the recombination of D(3)(+) ions with electrons at temperatures from 77 to 300 K. A linear dependence of apparent (effective) binary recombination rate coefficients on the pressure of the helium buffer gas was observed. Binary (D(3)(+)+e(-)) and ternary (D(3)(+)+e(-)+He) recombination rate coefficients were derived. The obtained binary rate coefficient agrees with recent theoretical values for dissociative recombination of D(3)(+). We describe the observed ternary process by a mechanism with two rate determining steps. In the first step, a rotationally excited long-lived neutral D(3)* is formed in D(3)(+)-e(-) collisions. As the second step, the D(3)* collides with a helium atom that prevents autoionization of D(3)*. We calculate lifetimes of D(3)* formed from ortho-, para-, or metastates of D(3)(+) and use the lifetimes to calculate ternary recombination rate coefficients.

Binary and ternary recombination of ${\rm D}_3^+$D3+ ions at 80–130 K: Application of laser absorption spectroscopy

“…We have demonstrated in our previous studies [16][17][18] and here we will demonstrate again, that the overall recombination of D + 3 in afterglow plasma can be described in this way. To obtain α bin and K He one has to measure the dependence of α eff on [He] at fixed temperature T.…”

“…For details on recombination studies of the D + 3 ion, see Refs. [9][10][11][12][13][14][15][16][17][18][19]. For both H + 3 and D + 3 significant differences between recombination rate coefficients were obtained in different types of experiments 10, 12-15, 19, 20 over many years and the differences between the experimental values and the theoretical ones were very large.…”

“…15 In our recent studies, we discovered a fast ternary neutral assisted recombination of H + 3 and D + 3 ions in plasma. [16][17][18][35][36][37] At temperatures between 77 and 300 K in helium buffer gas, the losses due to this ternary process are comparable with the losses due to binary dissociative recombination already at a buffer gas pressure of few hundred Pa. When this process is accounted for, then the rate coefficient of binary process can be obtained from afterglow experiments.…”

Cryo-FALP study of collisional-radiative recombination of Ar+ions at 40–200 K

“…[15]) apparatusCryo-FALP (for details on the previous versions of FALP apparatuses operating at higher pressure see refs. [16][17][18][19]) was build and used to study CRR at temperatures down to 40 K. Scheme of the Cryo-FALP is shown in Figure 1. Helium buffer gas (300 -800 Pa) is flowing through a glass discharge tube into a stainless steel flow tube.…”

The impact of recent advances in laboratory astrophysics on our understanding of the cosmos

“…The analysis is dependent on an accurate determination of the dissociative recombination rate coefficient, which until recently was poorly known. Measurements using storage rings (McCall et al 2003;Kreckel et al 2005;Tom et al 2009;Kreckel et al 2010) and afterglows (Glosik et al 2008(Glosik et al , 2009Kotrík et al 2010), as well as theoretical calculations (Dos Santos et al 2007), are now converging on the most appropriate value for the rate coefficient. The cosmic ray ionization rate in diffuse molecular clouds inferred from H + 3 observations is now more secure (e.g., Indriolo et al 2007).…”