Production yields of H(D) atoms in the reactions of N2(AΣu+3) with C2H2, C2H4, and their deuterated variants

Abstract

The production yields of H(D) atoms in the reactions of N(2)(A (3)Sigma(u) (+)) with C(2)H(2), C(2)H(4), and their deuterated variants were determined. N(2)(A (3)Sigma(u) (+)) was produced by excitation transfer between Xe(6s[32](1)) and ground-state N(2) followed by collisional relaxation. Xe(6s[32](1)) was produced by two-photon laser excitation of Xe(6p[12](0)) followed by concomitant amplified spontaneous emission. H(D) atoms were detected by using vacuum-ultraviolet laser-induced fluorescence (LIF). The H(D)-atom yields were evaluated from the LIF intensities and the overall rate constants for the quenching, which were determined from the temporal profiles of the NO tracer emission. The absolute yields were evaluated by assuming that the yield for NH(3)(ND(3)) is 0.9. Although no HD isotope effects were observed in the overall rate constants, there were isotope effects in the H(D)-atom yields. The H-atom yields for C(2)H(2) and C(2)H(4) were 0.52 and 0.30, respectively, while the D-atom yields for C(2)D(2) and C(2)D(4) were 0.33 and 0.13, respectively. The presence of isotope effects in yields suggests that H(2)(D(2)) molecular elimination processes are competing and that molecular elimination is more dominant in deuterated species than in hydrides.

CRITICAL REVIEW OF N, N + , N + 2 , N ++ , And N ++ 2 MAIN PRODUCTION PROCESSES AND REACTIONS OF RELEVANCE TO TITAN'S ATMOSPHERE

“…Dreyer & Perner (1973) and Thomas et al (1987) measured a weak dependence of the rate constant with the vibrational energy of N 2 (A). Similarly to the case of acetylene, both the high rate constant and the quasi-absence of vibrational dependence are explained by the fact that this reaction produces the dissociation of C 2 H 4 , as shown by Umemoto (2007). Umemoto (2007) (±60%) Our recommended rate constant value is the same as the one recommended by Herron (1999) which is based on the measurements of Slanger et al (1973), slightly adjusted.…”

“…Bohmer & Heck (1991) did not observe any dependence of the rate constant with the vibrational energy of N 2 (A). Both the high rate constant and the absence of vibrational dependence are explained by the fact that, as opposed to reactions with N 2 , H 2 , and CH 4 , this reaction is not mainly quenching of N 2 (A) but produces the dissociation of C 2 H 2 , as shown by Umemoto et al (Umemoto 2007).…”

“…Umemoto (2007) measured the H atom yield and D atom yield to be equal to 0.52 and 0.33, for the reactions with C 2 H 2 and C 2 D 2 , respectively. They conclude that the presence of an (Herron 1999) N 2 (A 3 Σ + u ) + C 2 H 2 298 1.6 × 10 −10 P-CL N 2 (A 3 Σ + u ) + C 2 H 2 298 1.6 × 10 −10 FP-CL (Callear & Wood 1971) N 2 (A 3 Σ + u ) + C 2 H 2 298 2.5 × 10 −10 DF-CL (Meyer et al 1971) N 2 (A 3 Σ + u ) + C 2 H 2 298 2.0 × 10 −10 DF-LIF (Bohmer & Hack 1991) N 2 (A 3 Σ + u ) + C 2 H 2 298 2.0 × 10 −10 Compilation (Herron 1999) N 2 (A 3 Σ + u ) + C 2 H 2 298 (1.40 ± 0.02) × 10 −10 for C 2 H 2 LP-LIF (Umemoto 2007) (1.45 ± 0.03) × 10 −10 for C 2 D 2 N 2 (A 3 Σ + u ) + C 2 H 4 298 1.2 × 10 −10 FP-CL N 2 (A 3 Σ + u ) + C 2 H 4 298 1.5 × 10 −10 P-CL N 2 (A 3 Σ + u ) + C 2 H 4 298 1.1 × 10 −10 FP-CL (Callear & Wood 1971) N 2 (A 3 Σ + u ) + C 2 H 4 298 1.6 × 10 −10 DF-CL (Meyer et al 1971) N 2 (A 3 Σ + u ) + C 2 H 4 298 0.64 × 10 −10 DF-LIF (Dreyer & Perner 1973) N 2 (A 3 Σ + u ) + C 2 H 4 298 1.2 × 10 −10 DF-ES (Clark & Setser 1980) N 2 (A 3 Σ + u ) + C 2 H 4 298 1.2 × 10 −10 DF-CL (Cao & Setser 1985) N 2 (A 3 Σ + u ) + C 2 H 4 298 1.0 × 10 −10 DF-LIF (Thomas et al 1987 N 2 (A 3 Σ + u ) + C 2 H 6 298 3.6 × 10 −13 FP-CL (Callear & Wood 1971) N 2 (A 3 Σ + u ) + C 2 H 6 298 2 × 10 −14 DF-CL (Meyer et al 1971) N 2 (A 3 Σ + u ) + C 2 H 6 298 2.9 × 10 −13 PR-AS (Dreyer & Perner 1973) N 2 (A 3 Σ + u ) + C 2 H 6 300-370 2.2 × 10 −13 a FP-CL (Slanger et al 1973) N 2 (A 3 Σ + u ) + C 2 H 6 298 2.3 × 10 −13 Compilation (Herron 1999) (Husain et al 1972) N ( 2 D) + N 2 298 1.5 × 10 −14 FP-RA (Husain et al 1974) N ( 2 D) + N 2 298 1.8 × 10 −14 FP-CL ) Sugawara et al 1980) N ( 2 D) + N 2 213-294 2.4 × 10 −14a PR-RA (Suzuki et al 1993b) N ( 2 D) + N 2 298 1.7 × 10 −14 Compilation (Herron 1999) N ( 2 P ) + N 2 400 6 × 10 −14 DF-RA (Lin & Kaufman 1971) N ( 2 P ) + N 2 298 3 × 10 −16 DF-RA (Husain et al 1972) N ( 2 P ) + N 2 298 1.0 × 10 −16 FP-RA (Husain et al 1974)…”

“…This reaction has a high rate constant and the different measurements are in rather good agreement (see Table 3). We recommend the most recent rate constant value measured by Umemoto (2007), with an uncertainty that takes into account the scattering of the rate constants measured by other authors. Umemoto also studied the reaction with C 2 D 2 which has almost the same rate constant as for C 2 H 2 .…”

Kinetic mechanism of molecular energy transfer and chemical reactions in low-temperature air-fuel plasmas

“…product distributions of hydrocarbon dissociation by electron impact and during quenching of electronically excited N 2 molecules and O atoms has not been studied in detail, although some experimental results are available [24,30,31], and therefore remains fairly uncertain. Further experimental studies of different dissociation channels in these reactions may well reduce the uncertainty in the kinetic modelling predictions and are therefore highly desirable.…”