Ionization, theory

A practical application coming out of field ion emission is the liquid metal ion source. Ion sources of a wide variety of chemical elements, most of them low melting point metals, can be produced by using either liquid metals131,132 or liquid alloys.133 The idea of extracting charged droplets out of liquid by application of an electrostatic field is perhaps older than field ion microscopy. But the development of liquid metal ion sources from liquid capillaries, from slit shaped emitter modules and from wetted field emission tips, etc., as well as the understanding of the mechanisms of ion formation in terms of field evaporation and field ionization theories,... 

The charge properties of amino acids are very important in determining the reactivity of certain amino acid side chains and in the properties they confer on proteins. The charge properties of amino acids in aqueous solution may best be considered under the general treatment of acid-base ionization theory. We find this treatment useful at other points in the text as well. 

Ionization of liquid ammonia and water solutions.—Solutions of certain salts in liquid ammonia are good conductors of electricity so that liquid ammonia approaches water in its ionizing power. The effect, however, is largely due to the high speed at which the ions are supposed to travel in the solvent. For example, E. C. Franklin and H. P. Cady1 find that univalent ions travel, at —33°, nearly three lames as fast as in aq. soln. at 18°. Just as the solvent water, in the ionization theory of hydrolysis, is supposed to be ionized H20=0H -f-H, so in ammonolysis, the solvent ammonia is supposed to be ionized NH3==NH2-j-H . Sodamide, NaNH, furnishes sodium ions Na and amide ions NH 2 when dissolved in liquid ammonia, and it is to be considered as a base. It reddens phenolphthalein. The neutralization of this solution results in the union of H ions with NH2 ions to form ammonia molecules, just as the neutralization of bases is regarded as an effect of the union of H and OH ions. Acetamide, CH3.CO.NH2, ionizes in liquid ammonia in an analogous manner CH3.CO.NH2 CH3.CO.NH -f-H, and it thus behaves as an acid. 

There is nothing new in principle about the use of isotopes as an aid to chemistry. For twenty years the radioactive elements have been used as indicators to study adsorption, solubility, volatility, distribution, and other phenomena of physical chemistry. Distribution of heavy radioactive atoms in plants has been studied through the relative amount of ionization found in the different parts. The ionization theory was supported by dissolving radioactive lead chloride in an aqueous solution of ordinary lead nitrate and then crystallizing out the lead chloride. The radioactive lead was found to be equally distributed between the two salts. In aqueous solution the two different kinds of lead are free to exchange anions, as predicted from the electrolytic dissociation theory. With un-ionized compounds of lead it was found that exchange does not take place. 

In James Kendall Journal of Chemical Education The Present Status of the Ionization Theory Volume 2, Number 5, May 1925 (p. 376)... 

Because of problems in the measurement of a, quantification is normally carried out either by relative sensitivity factor methods or by semi-empirical approximations to a based on one of the ionization theories. 

Electrolytic Dissociation or Ionization Theory n When an acid, base or salt is dissolved in water or any other dissociating solvent, a part or all of the molecules of the dissolved substance are broken up into parts called ions, some of which are charged with positive electricity and are called cations, and an equivalent number of which are charged with negative electricity and are called anions. 

See also Chemical Ionization in Mass Spectrometry Fast Atom Bombardment Ionization in Mass Spectrometry Fragmentation in Mass Spectrometry Ion Structures in Mass Spectrometry Ion Trap Mass Spectrometers Ionization Theory Ion Energetics in Mass Spectrometry Ion Collision Theory Metastable Ions Quadrupoles, Use of in Mass Spectrometry Sector Mass Spectrometers Statistical Theory of Mass Spectra Time of Flight Mass Spectrometers. 

See also Ion Dissociation Kinetics, Mass Spectrometry Ion Energetics in Mass Spectrometry Ionization Theory Multiphoton Excitation in Mass Spectrometry Photoelectron-Photoion Coincidence Methods in Mass Spectrometry (PEPICO) Spectroscopy of Ions Time of Flight Mass Spectrometers. 

See also Ionization Theory Thermospray ionization in Mass Spectrometry. 

NMR Spectroscopy Ionization Theory Ion Molecule Reactions in Mass Spectrometry Negative Ion Mass Spectrometry, Methods Photoionization and Photodissociation Methods in Mass Spectrometry Quadru-poles. Use of in Mass Spectrometry Time of Flight Mass Spectrometers. 

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