Kinetics of electron attachment to SF3CN, SF3C6F5, and SF3 and mutual neutralization of Ar+ with CN− and C6F5−

Abstract

The additions of two sulfur fluoride derivatives (SF(3)C(6)F(5) and SF(3)CN) to a flowing afterglow were studied by variable electron and neutral density mass spectrometry. Data collection and analysis were complicated by the high reactivity of the neutral species. Both species readily dissociatively attach thermal electrons at 300 K to yield SF(3) + X(-) (X = C(6)F(5), CN). Attachment to SF(3)C(6)F(5) also results in SF(3)(-) + C(6)F(5) as a minor product channel. The determined electron attachment rate constants were 1(-0.6) (+1) × 10(-7) cm(3) s(-1) for SF(3)C(6)F(5), a lower limit of 1 × 10(-8) cm(3) s(-1) for SF(3)CN, and 4 ± 3 × 10(-9) cm(3) s(-1) for SF(3). Mutual neutralization rate constants of C(6)F(5)(-) and CN(-) with Ar(+) at 300 K were determined to be 5.5(-1.6) (+1.0) × 10(-8) and 3.0 ± 1 × 10(-8) cm(3) s(-1), respectively.

Electron Attachment to Fe(CO)n (n = 0–5)

“…By also accounting for diffusive electron loss, the rate constant of electron attachment to the neutral species may be determined by the measured rate of electron depletion. − With the exception of a few special cases, the conventional FALP technique is not suited to studying short-lived species because they are not easily delivered into the flow tube. The VENDAMS technique uses an identical FALP apparatus but exploits dissociative electron attachment to the added neutral species and mutual neutralization of the resulting anions with Ar + as a source for such short-lived species. − , Instead of monitoring electron or ion concentration along the flow tube, in VENDAMS the Langmuir probe is held at the neutral inlet and used to measure the initial electron density ([e] 0 ) at time zero as the neutral gas is added. Product anion abundances at the end of the flow tube (after a known reaction time) are measured as a function of [e] 0 .…”

Dissociative electron attachment to C2F5 radicals

“…15 VENDAMS allows for measurements of attachment to short lived species, such as radicals, and a variety of information on ion-ion mutual neutralization kinetics. [16][17][18][19] The technique has been described in detail previously 15,17 and only the aspects important to the present experiments are described here. A primarily Ar + /e − plasma is formed by a microwave discharge in pure He with Ar added downstream at 4% of the He flow rate to convert He + 2 and He metastables to Ar + .…”

A novel technique for measurement of thermal rate constants and temperature dependences of dissociative recombination: CO2+, CF3+, N2O+, C7H8+, C7H7+, C6H6+, C6H5+, C5H6+, C4H4+, and C3H3+

“…The technique, dubbed variable electron and neutral density attachment mass spectrometry (VENDAMS), 11 has been applied to measure rate constants and product distributions of mutual neutralization [12][13][14][15][16] and electron attachment to short-lived species such as radicals. 11,17,18 Here, a variation of the technique is used to determine thermal DR rate constants.…”