Results 211 to 220 of about 37,547 (266)
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Ionization of metal vapours in a flame
Physica, 1948Abstract In an ordinary acetylene-air-flame the vapours of potassium and rubidium at low concentrations are ionized to a considerable degree. At higher concentrations the resonance lines of these elements are strongly self-absorbed. Moreover the atoms associate to molecules. It is very difficult to measure these resonance lines in a hot flame without
J.A Smit, A.J.H Vendrik
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Flame ionization of iron and lead
Australian Journal of Chemistry, 1983The mass spectra of ions in flame ionization detector (f.i.d.) type flames containing iron and lead compounds show that, in addition to metal ions, prominent species of formula (MoxHx+1)+ are present which are apparently protonated metal hydroxides. For FeOH2+ and PbOH2+, however, the structure of these species may be identical with those of metal-ion ...
NS Ham, T McAllister
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Ionization and recombination in flames
Proceedings of the Royal Society of London. A. Mathematical and Physical Sciences, 1976Abstract The enigma presented by the apparently straightforward experimental result that argon is about as effective as molecular gases in ionizing metals in flames is resolved. The theory described is consistent with the more recent measured ionization rate coefficients in the composite burnt gases (Kelly & Padley 1972) but ...
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Thermal and chemical ionization in flames
Combustion, Explosion and Shock Waves, 1970We have determined the rate constants of the potassium ionization process A→A++e− in the flames of 2H2+O2+X (Ar, He) mixtures on the temperature interval 1500–2500° K. The activation energy of this process is close to the ionization potential of potassium (100 kcal).
E. S. Semenov, A. S. Sokolik
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Ionization Cross Sections in Flames
The Journal of Chemical Physics, 1972A model is described based on the Chew—Low approximation which accounts quantitatively for recent measurements of ionization rates of alkali metals in CO/O2/N2 or H2O2N2 flames. The basic physics of the model is the same as that proposed by Hollander; that is to say the ionization of the alkali metal takes place from a state close to the ionization ...
G. N. Fowler, T. W. Preist
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A Hydrogen Singing-flame Ionization Detector
Nature, 1964THE sensitivity of an ordinary hydrogen flame ionization detector to hydrocarbons has been found to be two to three times higher when the detector flame ‘whistles’ or ‘sings’. Further investigation of this phenomenon has disclosed the probable reasons for the enhanced sensitivity and has uncovered other useful characteristics of the singing-flame ...
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Chemi-ionization in oxyacetylene flames
Nature, 1982The identity of the first ion formed in hydrocarbon flames has created much discussion. Two species have been favoured1–7, produced in the chemi-ionization processes: CH + O → CHO+ + e− (1) CH* + C2H2 → C3H3+ + e− (2) Reaction (2) is usually taken to involve electronically excited CH, in which case reaction (2), like reaction (1) with ground state CH ...
A. N. Hayhurst, H. R. N. Jones
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1979
The ion chemistry which proceeds in natural hydrocarbon flames, in particular CH4/O2 flames, is viewed from the perspective provided by recent room-temperature measurements of individual ion-molecule reactions. Limited reaction schemes are proposed for both positive and negative ions in the preheat region, the reaction zone, and the burnt gas ...
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The ion chemistry which proceeds in natural hydrocarbon flames, in particular CH4/O2 flames, is viewed from the perspective provided by recent room-temperature measurements of individual ion-molecule reactions. Limited reaction schemes are proposed for both positive and negative ions in the preheat region, the reaction zone, and the burnt gas ...
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Sensitivity of a planar micro-flame ionization detector
Talanta, 2010The sensitivity of a MEMS μFID with reduced fuel gas consumption for portable applications like mobile GC or THA is examined. It is shown that sensitivity depends on flame size and type of sample gas supply (either separate supply or premixed with the hydroxygen).
Winfred, Kuipers, Jörg, Müller
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Ionization of Metal Atoms in Flames
Spectroscopy Letters, 1971Abstract The ionization of free atoms in flames is a well-known effect and its relevance in atomic absorption spectroscopy is discussed in standard texts (1), (2) For analytical purposes it is important to know whether the degree of ionization will be significant for a given element under selected operating conditions.
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