Collisions with ions

All three types of discharge involve the formation of ions as part of the process. For various reasons, most of the ions are positive. The ions can be examined by mass spectrometry. If small amounts of a sample substance are introduced into a corona or plasma or arc, ions are formed by the electrons present in the discharge or by collision with ions of the discharge gas. 

Chains, Stokes law with, 68-70 Chan, T., 120 Chapman, S. J., 168-169 Characteristic charge, 187 Characteristic length and diffusion, 155 Charging mechanisms, 179 collisions with ions, 185 contact electrification, 182-183 corona discharge, 195-198 diffusion, 185-189,195 electric, 179-183 equilibrium with, 200-201 steady-state theory of, 201-207 transient approach to, 207-208 field charging, 185,189-195 flame ionization, 184-185 and force, 179-180 frictional, 184... 

Oil droplets were charged by collisions with ions. In the absence of an additional potential, they fell under the force of gravity. In the presence... 

Most modern mass spectrometers are designed so that electron-impact ionization and chemical ionization can be carried out interchangeably. Such sources are called EI-Cl sources. In chemical ionization, gaseous atoms of the sample (from either a batch inlet or a heated probe) are ionized by collision with ions produced by electron bombardment of an excess of a reagent gas. Usually, positive ions are used, but negative ion chemical ionization is occasionally used with analytes that contain very electronegative atoms. Chemical ionization is probably the second-most common procedure for producing ions for mass spectrometry. ... 

Because the ion trap contains ions of all values of m/z at the same time (as well as neutral molecules that were not ionized prior to entering the trap), ion trap mass analyzers are also sensitive to overload and ion-molecule collisions that complicate the resulting spectrum. Recall that not all of the sample molecules get ionized—many remain uncharged. These neutral species move in a random path in the ion trap, resulting in collisions with ions as the ions oscillate in their stable trajectories. These collisions result in chemical ionization-type ionization events (Equation 3.20). This is sometimes referred to as self-CI. 

During sputtering, the atoms can then be collisionally excited. These collisions may be with ions, electrons, or other atoms that have been previously excited by collisions with ions, electrons, or atoms. Once excited, atoms lose their energy very quickly. In optical atomic spectroscopy, the wavelength of this photon can be used to determine the identity of the atom, and the number of photons is directly proportional to the concentration of that element in the sample. Some collisions, which are of high energy, result in ionization. By atomic mass spectrometry, these ions are detected. Their mass identifies the type of atoms, and their quantity reveals the amount of that element in the sample. 

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