Ion repeller

Efforts to provide such a treatment for simple alternative structures, such as the sodium chloride and cesium chloride structures and the fluoride and rutile structures, have been made with the aid of the Bom potential expression and modifications of it. Assuming that all ions repel each... 

Ionically bonded crystals contain both long-range and short-range bonding forces because like ions repel each other, while unlike ones attract. 

The El source is formed by a tungsten or rhenium filament, an anode, an ion repeller, a magnet, and a series of lenses for extracting, focusing and accelerating the ions formed (Figure 2.2). 

Figure 2.2 Schematic view of the electron ionization source, a, Ion repeller h, anode c, acceleration and focalization plates N, S, magnet poles...

Ionic compounds are brittle but not ductile, as is shown in Figure 1. When they are hammered, their structure is disturbed, the hammered part shifts and similar charged ions repel each other and the ionic substance breaks down into smaller pieces. Since movement of the ions disturbs the balance of electrical charge, ionic solids cannot be drawn into wires and are broken easily. 

An ISI is used with less polar effluents and is the workhorse for standard HPLC systems since it can take flow rates up to 2mL/min. It is most commonly used to produce intact molecular ions for molecular weight determinations, but it can be set up with an ion repeller to cause fragmentation that can provide preliminary compound identification and structural information. 

Figure 16.9 Triamine-based gating strategy (a) at high pH the amine groups interact with each other and the pore wall through hydrogen bonding and the gate is open (b) at low pH the protonated ammonium ions repel each other, closing the gate (c) in the presence of bulky polyvalent counterions the pores are effectively sealed.

As the ions repel each other in the trap, their trajectories expand as a function of the time. To avoid ion losses by this expansion, care has to be taken to reduce the trajectory. This is accomplished by maintaining in the trap a pressure of helium gas which removes excess energy from the ions by collision. This pressure hovers around 10-3 Torr (0.13 Pa). A single high-vacuum pump with a flow of about 401 s-1 is sufficient to maintain such a vacuum compared with the 2501 s-1 needed for other mass spectrometers. The instrument is very simple and relatively inexpensive. 

Once an electron has been received the uninegative ion repels further electrons hence the negative affinities displayed by oxide, sulphide and selenide 2-negative ions. 

S. Auriola, T. Naaranlahti, R. Kostiainen, S.P. Lapinjoki, Identification of indole alkaloids of Catharanthus roseus with LC-MS using CID with the TSP ion repeller, Biomed. Environ. Mass Spectrom., 19 (1990) 400. 

Both repulsive and attractive forces exist within a salt crystal. The repulsive forces include those between like-charged ions. Within the crystal, each Na" ion repels the other Na" ions. The same is true for the Cl ions. Another repulsive force exists between the electrons of ions that are close together, even if the ions have opposite charges. 

TABLE IV. Positive Ion Repeller-induced Fragmentation Spectra of Chlorinated Acid Herbicides... 

N-C Hj-morphine as internal standard. The internal standard was added to 10 ml urine, the urine buffered to pH 8.5 and extracted with chloroform isopropanol (4 1). The extraction residue was trimethylsilylated by adding 25 ul of N,0-bis(trimethylsilylJacetamide and heating at 60°C for about 1 h. About 2 ul was analyzed on a 3 % 0V-17 column at 230°C coupled direct to a Finnegan 1015 quadrupole mass spectrometer equipped with a chemical ionization source, which was operated at an ionizing energy of 100 eV, an ion repeller voltage of 0 V and a filament emission of 300 uA. The mass spectrometer was interfaced with a System Indus-... 

Due to the presence of V>d,D counterions of the primary charges are accumulated in the Donnan phase and co-ions repelled. In equilibrium the electrochemical potentials of the small ions at each side of the membrane must be the same, this can be expressed as ... 

Problem Oppositely charged ions are attracted in rock salt crystal (Na+ and Cl-), similarly charged ions repel each other (Na+ and Na+, Cl- and Cl-). The attraction of all ions in salt crystals can be explained by the balance of attraction and repulsion forces. It is difficult to create such a model showing electric forces. It is, however, possible to implement a model for demonstration purposes with a balance of magnetic attraction and repulsion forces which thereby simulates a two-dimensional crystal. 

Electrons in the partly filled orbitals of a metal ion repel one another and give rise to a number of energy levels depending upon the arrangement of these electrons in the d-orbitals. The energy of each of these levels can be expressed in terms of some inter-electronic repulsion parameters. It is observed experimentally that magnitude of these inter-electronic repulsion parameters always decreases on the Transition Elements... 

Electrons on the zinc attract them, the other zinc ions repel them. 

For the doubly charged helium molecule-ion, He +, a treatment Pased on the function 43-13 has been carried through,3 leading to the energy curve shown in Figure 43-5. It is seen that at large distances the two normal He+ ions repel each other with the force e2/r2. At about 1.3 A the effect of the resonance integrals... 

To determine the abundance of neutral species, methane at 6 X 10 ° torr was irradiated in Compartment B by EB-B with 100 e.v. electrons. Positive ions thus formed were collected by applying a negative potential on the ion repeller, while the neutral species diffused into C. EB-C, adjusted to an electron energy below the ionization potential of CH4 (i.e., < 13.0 e.v.), ionized neutral species except for H and H2. For these species the electron energy of EB-C was raised to about 16 e.v. Runs were then made with the energy of EB-B approximately zero, all other conditions being identical. The difference-in intensity of a given ion was taken to be the intensity of the neutral species produced by the 100 e.v. electrons in B by Reactions II and III. The cross sections for the production of primary neutral species were reported previously (39). 

A different type of anionic complex is the dark blue Cr2C l which is made by the procedure used for similar compounds of V, Ti, T1 and W, namely, interaction of CrCl3 and CsCl at 650-850°. The ion has three bridging Cl atoms and is similar to W2C1 - (page 961) except that the Cr3+ ions repel each other from the centers of their octahedra and the magnetic moments are normal, indicating that there is no Cr—Cr bond.19... 

When a force is applied to the crystal, the layers of ions in the crystal structure can slip so that similarly charged ions are next to one another. The like charges of the ions repel one another and the crystal structure shatters, see Fig. 4.5. 

Therefore, it is difficult to concentrate any given ionic species for two reasons first, the concentration of any species must occur against a potential gradient that tends toward dispersion and, second, similar ions repel each other, which also tends toward dispersion. 

Solution Ion-source block = 8000 V electron filament (cathode) = 7930 V electron trap = about 8100 V ion repeller = about 8020 V and the exit slit at ground potential (i.e., at 0 V). 

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