14067-05-1Relevant articles and documents
Exothermic ion-molecule reactions
Moran,Friedman
, p. 3837 - 3845 (1966)
Dissociative charge-transfer reactions between rare-gas He+, Ne+ ions and diatomic N2, O2, CO, NO molecules have been studied as a function of reactant-ion velocity. N+, O +, and C+ fragment ions are the major reaction products observed in these exothermic reactions. Experimental cross sections and corresponding rate constants for thermal-energy ions are in semiquantitative agreement with the theoretical rates calculated from the long-range ion-induced-dipole potential. A reversed-repeller technique was used to probe the kinetic-energy distributions of the ionic reaction products and the experimental (0.2 to 1 eV) distributions so obtained are well correlated with the heats of the respective reactions. The kinetic energies of the product N+ and O+ ions were shifted to lower values when 3He+ was substituted for 4He+ ions in the NO and O2 reactions. This shift in product-ion kinetic energy rules out accidentally resonant chargetransfer processes involving excited product atoms and is consistent with a two-body breakup mechanism of transitory HeN+ and HeO+ at low reactant-ion velocities.
Absolute state-selected and state-to-state total cross sections for the Ar+(2P3/2,1/2) + CO2 reactions
Flesch, G. D.,Ng, C. Y.
, p. 162 - 172 (2007/10/02)
Absolute spin-orbit state-selected total cross sections for the reactions, Ar+(2P3/2,1/2) + CO2 -> CO2+ + Ar , CO+ + O + Ar , O+ + CO + Ar , C+ + 2O + Ar , ArC+ + 2O , ArO+ + CO , and ArCO+ + O have been measured in the center-of-mass collision energy (Ec.m.) range of 0.26-131 eV.The ratio of the charge-transfer cross section due to Ar+ (2P1/2) to that associated with Ar+ (2P3/2) varies in the range of 0.5-0.8.The appearance energies observed for CO+ (Ec.m. = 4.2 +/- 0.5 eV), O+ (Ec.m. = 3.7 +/- 0.5 eV), and C+ (Ec.m. = 12.6 +/- 0.5 eV) are in agreement with the thermochemical thresholds for reactions (2), (3), and (4), respectively.The comparison of the absolute cross sections for CO+, O+, and C+ from CO2 by photoionization and by dissociative charge transfer is made.The kinetic-energy analysis of product CO2+, CO+, O+, C+, ArO+, and ArC+ suggests that reactions (2)-(7) proceed via a charge-transfer predissociation mechanism.This experiment, together with the previous studies of Ar+ (2P3/2,1/2) + N2 (O2,CO), supports the conclusion that product ions formed by dissociative photoionization are also produced by dissociative charge transfer.We find that the absolute cross sections for product ions formed in the dissociative charge-tranfer processes are substantially greater than those formed in the dissociative photoionization of CO2, a finding consistent with the general observation that photoionization cross sections are significantly smaller than charge-transfer cross sections.The relative cross sections for CO+, O+, and C+ formed by reactions (2)-(4) are also found to be different from those for photoionization of CO2.This difference is attributed to the anisotropic interaction potential surface responsible for the Ar+ (2P3/2,1/2) + CO2 reactions.
Reactions of Carbonyl Sulfide in a Radio-Frequency Plasma
Bezuk, Steve J.,Miller, Larry L.,Platzner, I.
, p. 131 - 136 (2007/10/02)
Carbonyl sulfide was flowed through the plasma zone of a 13.6-MHz inductively coupled discharge.The active plasma was sampled by mass and emission spectroscopy.Typical conditions were as follows: power, 5-25 W; pressure, 0.1-0.3 torr; flow rate, 4 cm3 min-1.Mass spectrometry showed the neutrals CO, S, and S2 as products.The major ions were COS+, S+, S2+, S3+, CO+, and CS2+.The variations in the ionic composition as pressure and power were changed were studied.Reaction products coat the reactor walls after some time and it was shown that this deposit could be sputtered with a CO or Ar plasma to produce sulfur-containing ions.Experiments using a small amount of 2-butyne as coreactant with COS suggested that this hydrocarbon reacted with sulfur atoms.Comparison with the chemistry of butane plus COS was made.Emission spectroscopy showed major bands due to CO* and CS*.S* emission had a lower intensity.It was shown that 5 mol percent of SF6 quenched much of the CS* emission.It is suggested that CS* is formed from electron-COS+ recombination.
