Dissociative recombination at elevated temperatures. IV. N₂⁺dominated afterglows

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

“…No uncertainty is given with respect to the power-law exponent, but an error of 20% seems reasonable. A theoretical work by Guberman (2003) concluded that the electron temperature dependence is slightly different for 600 K T e 3000 K. Considering now the absolute rate constant k, analysis of the literature shows that several experiments (Canosa et al 1991;Cunningham & Hobson 1972;Geoghegan et al 1991;Mehr & Biondi 1969) …”

“…They have observed only dissociative charge transfer products with branching ratios (T e /300) −0.39 cm 3 s −1 (±25%). The dissociative recombination of N + 2 has been extensively studied, both experimentally (Canosa et al 1991;Cunningham & Hobson 1972;Geoghegan et al 1991;Kasner 1967;Kella et al 1996;Mahdavi et al 1971;Mehr & Biondi 1969;Mul & McGowan 1979;Noren et al 1989;Oddone et al 1997;Peterson et al 1998;Queffelec et al 1985;Sheehan & St. Maurice 2004;Zipf 1980) and theoretically (Guberman 1991(Guberman , 2003(Guberman , 2012Guberman et al 1993). The interest in the reaction arises because of its involvement in Earth's atmosphere photochemistry (Fox & Dalgarno 1985;Torr & Torr 1979), and more generally in the chemistry of terrestrial planet ionospheres (Fox 1992(Fox , 1993Fox et al 1993).…”

“…From an experimental point of view, two classes of studies have been carried out: those measuring directly the rate constant k (Canosa et al 1991;Cunningham & Hobson 1972;Geoghegan et al 1991;Kasner 1967;Mahdavi et al 1971;Mehr & Biondi 1969;Zipf 1980) and those which determined cross sections as a function of the relative energy of the N + 2 ions and electrons (Kella et al 1996;Mul & McGowan 1979;Noren et al 1989;Oddone et al 1997;Peterson et al 1998;Sheehan & St. Maurice 2004). The latter were then able to derive a rate constant by averaging the cross section over a Maxwellian energy distribution.…”

“…In 1969, Mehr & Biondi (1969) studied the dissociative recombination of N + 2 (v = 0) within the temperature range 300 K T e 5000 K using an afterglow apparatus, then in 1972, Cunningham & Hobson (1972) studied this process in a reduced temperature range, 700-2700 K, using a shock tube experiment. Both experiments were in good agreement with each other and led to a temperature dependence of k (T e ) ∼ T −n e (with n = 0.39 or 0.37, respectively).…”

Theoretical investigation of a photoconductively switched high-voltage spark gap

“…The rate coefficient k DR for this rapid process had been obtained by Cunningham and Hobson 35 and is given by k DR = 1.47 ϫ 10 −12 ͑T e ͓K͔͒ −0.37 m 3 s −1 . ͑9͒…”