Energetics ionization

The spark source is an energetic ionization process, producing a rich spectrum of multiply charged species (Af/2, Af/3, Af/4, etc.). These masses, falling at halves, thirds, and fourths of the unit mass separation can aid in the positive identification of elements. In Figure 2, species like Au and are labeled. The most abundant... 

Radioactivity is the process by which atoms emit energetic, ionizing particles or rays. These particles or rays are termed radiation. Nuclear radiation occurs because the nucleus is unstable, hence radioactive. Nuclear symbols consist of the elemental symbol, the atomic number, and the mass number. 

FIG. 7.1. Track formed by energetic ionizing particle in condensed matter. Distances between ion pairs along track are 1000 nm y, 500-100 nm fast electron, 1 nm slow electron and a. 

Example 2.3 Suppose that a compound with PA = 205 kcalmor is ionized by Cl with either H2 or isobutane as the reagent gas. Which gas will provide more energetic ionization ... 

Any source of energetic ionizing or non-ionizing radiation is potentially hazardous if not used correctly. All UV light sources must be well shielded. Skin and eyes should always be protected from exposure to UV light." ... 

The NIST Chemistry WebBook supports a variety of searches for chemical species. Each search type has its own associated Web page. Search types currently available are genoal, physical property, formula, chemical name, CAS registry number, ion energetics, ionization energy, electron affinity, proton affinity, acidity, vibrational and electronic energy... 

More energetic ionization methods (in-source decay, ISD) or collisions with inert (collision-activated dissociation, CAD, also known as collision-induced... 

Ionization with energetic electrons does not deposit a fixed amount of energy into a molecule. Rather, a 10 eV... 

If a sample solution is introduced into the center of the plasma, the constituent molecules are bombarded by the energetic atoms, ions, electrons, and even photons from the plasma itself. Under these vigorous conditions, sample molecules are both ionized and fragmented repeatedly until only their constituent elemental atoms or ions survive. The ions are drawn off into a mass analyzer for measurement of abundances and mJz values. Plasma torches provide a powerful method for introducing and ionizing a wide range of sample types into a mass spectrometer (inductively coupled plasma mass spectrometry, ICP/MS). 

Molecules can interact with energetic electrons to give ions (electron ionization, El), which are electrically charged entities. The interaction used to be called electron impact (also El), although no actual collision occurs. 

Spark (source) ionization. Occurs when a solid sample is vaporized and partially ionized by an intermittent electric discharge. Further ionization occurs in the discharge when gaseous atoms and small molecular moieties interact with energetic electrons in the intermittent discharge. It is recommended that the word source be dropped from this term. 

ST Russell, A Warshel. Calculations of electrostatic energies m proteins The energetics of ionized groups m bovine pancreatic trypsin inhibitor. J Mol Biol 185 389-404, 1985. 

Static Secondary Ion Mass Spectrometry (SIMS) involves the bombardment of a sample with an energetic (typically 1-10 keV) beam of particles, which may be either ions or neutrals. As a result of the interaction of these primary particles with the sample, species are ejected that have become ionized. These ejected species, known as secondary ions, are the analytical signal in SIMS. 

Sputtered Neutral Mass Spectrometry (SNMS) is the mass spectrometric analysis of sputtered atoms ejected from a solid surface by energetic ion bombardment. The sputtered atoms are ionized for mass spectrometric analysis by a mechanism separate from the sputtering atomization. As such, SNMS is complementary to Secondary Ion Mass Spectrometry (SIMS), which is the mass spectrometric analysis of sputtered ions, as distinct from sputtered atoms. The forte of SNMS analysis, compared to SIMS, is the accurate measurement of concentration depth profiles through chemically complex thin-film structures, including interfaces, with excellent depth resolution and to trace concentration levels. Genetically both SALI and GDMS are specific examples of SNMS. In this article we concentrate on post ionization only by electron impact. 

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