Dissociative recombination and mutual neutralization of heavier molecular ions: C10H8+, WF5+, and CnFm+

Abstract

Dissociative recombination (DR) rate coefficients for the naphthalene cation, C10H8(+), and WF5(+), and mutual neutralization (MN) rate coefficients for these species and five CnFm(+) ions, were determined at 300 K using variable electron and neutral density attachment mass spectrometry (VENDAMS). DR proceeds at 9 ± 3 × 10(-7) cm(3) s(-1) for C10H8(+) and at 6.1 ± 1.4 × 10(-7) cm(3) s(-1) for WF5(+). Consistent with previous results, MN for the polyatomic cations with the halide anions Cl(-), Br(-), and I(-) exhibits an approximate μ(-1/2) reduced mass dependence of the reactant partners, demonstrating that ion collision velocities influence the rate coefficients. This work is an extension of VENDAMS to systems, where low reactant concentrations are necessary to avoid significant reaction of product ions with the neutral precursor, i.e., conditions not suitable for traditional flowing afterglow measurements, as well as to ions of masses > ∼ 100 Da, which are not amenable to the study of DR in magnetic storage rings. Our results expand the sparse literature on DR and MN of heavier ions.

Negative Ions in Space

“…They conclude that their results are in agreement with ab initio calculations of Stenrup et al and theoretically calculated rate coefficients . A newer experimental approach was developed in the group of Viggiano and Miller that allows mutual neutralization to be investigated in flow-tube experiments at well-defined temperatures. − …”

The ion–ion recombination coefficient α: comparison of temperature- and pressure-dependent parameterisations for the troposphere and stratosphere

“…( 27). In addition, experiments with heavier molecular ions such as C 10 H + 8 , WF + 5 , and C 6 F + 11 support these findings (Wiens et al, 2015).…”

Mutual neutralisation of O+ with O−: investigation of the role of metastable ions in a combined experimental and theoretical study

“…Flowing Afterglow -Langmuir Probe (FALP). [15][16][17][18][19][20][21] Data are obtained under thermal 300-600 K conditions, and report several interesting conclusions: systems of four or more atoms react with very similar rate constants and triatomic systems somewhat slower, 16 while atom-atom systems proceed with widely varying rate constants. However, only under rare circumstances can the product distributions be measured and no information on the states of these products can be obtained.…”