Chemistry of Positive Ions. VI. Positive‐Ion Chemistry in Solid Methane

1966 ◽  
Vol 45 (12) ◽  
pp. 4481-4492 ◽  
Author(s):  
Donald R. Davis ◽  
W. F. Libby ◽  
W. G. Meinschein
Keyword(s):  
Ion Chemistry ◽  
Positive Ions ◽  
Positive Ion ◽  
Solid Methane

Hydrocarbon ions in fuel-rich, CH4–C2H2–O2 flames as a probe for the initiation of soot: an experimental approach

1981 ◽  
Vol 59 (12) ◽  
pp. 1760-1770 ◽  
Author(s):  
Scott D. Tanner ◽  
John M. Goodings ◽  
Diethard K. Bohme
Keyword(s):  
Reaction Zone ◽  
Soot Formation ◽  
Unsaturated Hydrocarbon ◽  
Ion Concentration ◽  
Negative Ion ◽  
Ion Chemistry ◽  
Positive Ions ◽  
Total Ionization ◽  
Ion Profiles ◽  
Positive Ion

The natural hydrocarbon ions CnHx± (n ≥ 2, x ≥ 0) present in premixed, fuel-rich, nearly sooting, CH4–C2H2–O2 flames at atmospheric pressure were studied as a probe of the early chemical stages of soot formation. Ion concentration profiles were measured mass-spectrometrically along the flame axis through the reaction zone into the burnt gas downstream. Total ionization profiles were examined for their dependence on both temperature and equivalence ratio, [Formula: see text] Families of individual CnHx− negative ion profiles exhibit concentration peaks in three distinct regions; predominantly oxygenated ions occur upstream, giving way to moderately unsaturated hydrocarbon ions near the end of the reaction zone, leading to highly unsaturated carbonaceous ions further downstream. The concentrations of the downstream ions alternate with the parity of n, the even-n species being larger. Series of CnHx+ positive ion profiles, for a given n, show profile peak positions which move steadily downstream with decreasing x, indicative of progressive dehydrogenation. The positive ion chemistry of these series is essentially independent of n. As [Formula: see text] is increased at constant temperature towards the sooting point, the concentrations of CnHx± ions increase while those of the oxygenated ions decrease; the positive ions show a relative enhancement of species having high values of n.

Note on radiationless transitions involving three-body collisions

1936 ◽  
Vol 32 (3) ◽  
pp. 482-485 ◽  
Author(s):  
R. A. Smith
Keyword(s):  
Continuous Spectrum ◽  
Negative Ions ◽  
Bound State ◽  
Excess Energy ◽  
Negative Ion ◽  
Positive Ions ◽  
Continuous State ◽  
Direct Formation ◽  
Three Body ◽  
Positive Ion

When an electron makes a transition from a continuous state to a bound state, for example in the case of neutralization of a positive ion or formation of a negative ion, its excess energy must be disposed of in some way. It is usually given off as radiation. In the case of neutralization of positive ions the radiation forms the well-known continuous spectrum. No such spectrum due to the direct formation of negative ions has, however, been observed. This process has been fully discussed in a recent paper by Massey and Smith. It is shown that in this case the spectrum would be difficult to observe.

PHOTOCHEMISTRY OF ELECTRONS TRAPPED IN GLASSES OF METHYLTETRAHYDROFURAN AT 77°K

1965 ◽  
Vol 43 (10) ◽  
pp. 2696-2707 ◽  
Author(s):  
P. J. Dyne ◽  
O. A. Miller
Keyword(s):  
Quantum Efficiency ◽  
Liquid Water ◽  
High Probability ◽  
Infrared Light ◽  
High Yield ◽  
Positive Ions ◽  
Positive Ion

In the radiolysis of methyltetrahydrofuran glass at 77°K electrons are produced with a high yield. These are immobilized in traps in the glass and do not recombine with positive ions. They can be released from their traps by illumination with visible and infrared light and may then diffuse to positive ions and be captured. The quantum efficiencies for bleaching have been measured as a function of wavelength. This quantum efficiency falls as bleaching proceeds and depends on the fraction of the electrons bleached and not on their concentrations. About half the electrons are trapped close to positive ions and, on release, have a high probability of diffusing to the positive ion. The remaining half are trapped homogeneously. On release from their traps, few of these electrons reach positive ions although they diffuse over long distances before being retrapped in the glass. This behavior is compared to that discussed by Samuel and Magee for the thermalization and capture of electrons in liquid water.

Positive ion chemistry of gaseous boric and polyboric acids

1992 ◽  
Vol 117 ◽  
pp. 47-63 ◽  
Author(s):  
Marina Attinà ◽  
Fulvio Cacace ◽  
Felice Grandinetti ◽  
Giorgio Occhiucci ◽  
Andreina Ricci
Keyword(s):  
Ion Chemistry ◽  
Positive Ion

scholarly journals Dissociation, recombination and attachment processes in the upper atmosphere II. The rate of recombination

1939 ◽  
Vol 170 (942) ◽  
pp. 322-340 ◽  
Keyword(s):  
Negative Ions ◽  
Neutral Molecule ◽  
Upper Atmosphere ◽  
The Other ◽  
Negative Ion ◽  
Neutral Atoms ◽  
Attachment Rate ◽  
Additional Advantage ◽  
Positive Ions ◽  
Positive Ion

The ionized regions of the upper atmosphere include, not only neutral atoms and molecules, electrons and positive ions, but also negative ions. Of these, electrons are alone effective in producing reflexion of wireless waves; so that an electron attached to a neutral molecule to form a negative ion is as effectively removed from active participation in these phenomena as one recombined with a positive ion to form a neutral molecule. The decay of electron density at night has been attributed by some authors to recombination with positive.ions and by others to attachment by neutral molecules. The first process is in agreement with the observed law of decay and has the additional advantage of making it easily possible to understand the formation of layers of concentrated ionization; on the other hand, the chance of attachment to a molecule per impact would have to be extremely small for the attachment rate to be negligible, since the number of collisions per second with neutral atoms is very much greater than with positive ions.

Positive Ion Chemistry of Elemental Fluorine

1997 ◽  
Vol 119 (40) ◽  
pp. 9499-9503 ◽  
Author(s):  
Romano Cipollini ◽  
Maria Elisa Crestoni ◽  
Simonetta Fornarini
Keyword(s):  
Ion Chemistry ◽  
Elemental Fluorine ◽  
Positive Ion
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