The radiation chemistry of CO has been studied, using principally low-energy protons from a Van de Graaff accelerator, as a function of dose rate, temperature and small amounts of additives (CO2 and O2). At dose rates higher than those used in previous work a true dose-rate inhibition effect has been found which is interpreted on the basis of competition between second-order and first-order processes. The effect of CO2 on yields is negligible at concentrations up to 0.5% by volume but initial yields are extremely sensitive to traces of O2, particularly at low dose rates.
Increased temperature reduces yields of solid and increases yields of CO2, but this effect is controlled mainly by subsequent thermal decomposition of the solid. The empirical composition of the solid is unaffected by changes in dose rate, and varies from (C3O2)n at room temperature to essentially pure carbon at temperatures >450°C. Nucleation of the solid occurs predominantly in the gas phase. The relative importance of ionic and excitation processes is discussed.
Temperature dependence of rate coefficients for reactions of ions with dipolar molecules
作者:D.C. Clary、D. Smith、N.G. Adams
DOI:10.1016/0009-2614(85)80425-5
日期:1985.9
We present a comparison of theoretical and experimental rate coefficients for the reactions of H3+, HCO+, H−, C+ and O+ with HCN, and H3+ with HCl, over the temperature range 205–540 K. The theoretical results are obtained using an adiabatic capture theory which is selective in the initial rotational states of the reacting dipolar molecules. The experiments were performed using a variable-temperature
Gas phase reaction rates of C+ with O2, NO and N2O near 0.6 K
作者:T.L. Mazely、M.A. Smith
DOI:10.1016/0009-2614(88)87316-0
日期:1988.5
measurement of absolute ion-molecule rateconstants, obtained using a novel free jet expansion flow reactor, at translational temperatures near 0.6 K. The reactions of C+ with O2, NO and N2O have been studied. All three reactions are found to have rateconstants significantly greater than those observed at 300 K. The observed rateconstants for reaction with NO and N2O can be explained upon consideration
High-Energy Oxygen Ions in Carbon Dioxide Mass Spectra
作者:R. M. S. HALL
DOI:10.1038/187683b0
日期:1960.8
MASSspectra of carbondioxide have been recorded using a low accelerating voltage and magnetic scanning. Under these conditions, a variant of those due to Mohler et al.1, ions with more than thermal energies will appear as satellite peaks in the spectra. The energies of the ions can then be derived from the separation of the peaks by the use of the mass spectrometer focusing equation.
Temperature dependence of ternary rate coefficients for the (CO)n−1++2CO⇌(CO)n++CO reaction, and the role of isomers for the growth of larger (CO)n+ clusters
作者:S. Schlemmer、A. Luca、J. Glosik、D. Gerlich
DOI:10.1063/1.1451247
日期:2002.3.15
Ternaryratecoefficients for the title reaction have been measured using a rf 22-pole ion trap in the temperature range 65–300 K. For the formation of dimers, the ternaryratecoefficient, k3, follows the power law 2.3×10−28 cm6/s×(300 K/T)m, with m=1.6±0.2 over the full temperature range of the experiment. This result is in good agreement with previous measurements at higher temperatures and also