Induced Ionization

Ionizing collisions between excited atoms or molecules and electrons represent the main ionization process in gas discharges. 

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REMPI Resonance-enhanced multi- Laser-induced ionization ... 

Rearrangement is especially prevalent with primary alkyl halides of the type RCH2CH2X and R2CHCH2X Aluminum chloride induces ionization with rearrangement to give a more stable carbocation Benzylic halides and acyl halides do not rearrange... 

Unlike the case of benzene in which ionization involves loss of a tt electron from the ring electron impact induced ionization of chlorobenzene involves loss of an elec tron from an unshared pair of chlorine The molecular ion then fragments by carbon-chlorine bond cleavage... 

A qualitatively different approach to probing multiple pathways is to interrogate the reaction intermediates directly, while they are following different pathways on the PES, using femtosecond time-resolved pump-probe spectroscopy [19]. In this case, the pump laser initiates the reaction, while the probe laser measures absorption, excites fluorescence, induces ionization, or creates some other observable that selectively probes each reaction pathway. For example, the ion states produced upon photoionization of a neutral species depend on the Franck-Condon overlap between the nuclear configuration of the neutral and the various ion states available. Photoelectron spectroscopy is a sensitive probe of the structural differences between neutrals and cations. If the structure and energetics of the ion states are well determined and sufficiently diverse in... 

The above examples should suffice to show how ion-molecule, dissociative recombination, and neutral-neutral reactions combine to form a variety of small species. Once neutral species are produced, they are destroyed by ion-molecule and neutral-neutral reactions. Stable species such as water and ammonia are depleted only via ion-molecule reactions. The dominant reactive ions in model calculations are the species HCO+, H3, H30+, He+, C+, and H+ many of then-reactions have been studied in the laboratory.41 Radicals such as OH can also be depleted via neutral-neutral reactions with atoms (see reactions 13, 15, 16) and, according to recent measurements, by selected reactions with stable species as well.18 Another loss mechanism in interstellar clouds is adsorption onto dust particles. Still another is photodestruction caused by ultraviolet photons produced when secondary electrons from cosmic ray-induced ionization excite H2, which subsequently fluoresces.42... 

MeV/amu Au53+ ions on helium, neon, and argon targets. These studies are also discussed in Section III. They show that the prediction of ultralow- and low-energy electrons in fast ion-induced ionization using the CDW-EIS model depend on the details of the target potential. 

Radiation induced ionization in an argon -filled detector. 

Electron ionization El Election induced ionization Volatile molecular ions Smaller molecules GC-MS Extensive libraries... 

Atmospheric pressure chemical ionization APCI Election induced ionization Nonvolatile molecular ions Smaller molecules LC-MS... 

CONTENTS Preface, Joseph Sneddon. Analyte Excitation Mechanisms in the Inductively Coupled Plasma, Kuang-Pang Li and J.D. Winefordner. Laser-Induced Ionization Spectrometry, Robert B. Green and Michael D. Seltzer. Sample Introduction in Atomic Spectroscopy, Joseph Sneddon. Background Correction Techniques in Atomic Absorption Spectrometry, G. Delude. Flow Injection Techniques for Atomic Spectrometry, Julian F. Tyson. 

Electrolytic oxidation or reduction may occur upon contact with the electrospray solution, triggering the formation of ions that normally do not exist in the bulk. Derivatization can be used to induce ionization for those compounds that do not carry redox groups [27,28],... 

The mechanism of heat generation is not clear at this stage. Final step of heat generation should be lattice vibration and the early step seems to be X-ray induced ionization, in-elastic scattering and the stopping of photoelectron. 

This process can be accounted for in terms of a consecutive two-photon-induced ionization. Absorption of the first photon results in the formation of the 2AP singlet excited state, and absorption of the second photon causes photoionization according to the following scheme ... 

R. D. Levine To answer the question of Prof. Lorquet, let me say that the peaks in the ZEKE spectra correspond to the different energy states of the ion. From the beginning one was able to resolve vibrational states, and nowadays individual rotational states of polyatomics have also been resolved. The ZEKE spectrum is obtained by a (weak) electrical-field-induced ionization of a high Rydberg electron moving about the ion. The very structure of the spectrum appears to me to point to the appropriate zero-order description of the states before ionization as definite rovibrational states of the ionic core, each of which has its own Rydberg series. Such a zero-order description is inverse to the one we use at far lower energies where each electronic state has its own set of distinct rovibrational states, known as the Bom-Oppenheimer limit. 

The term is restricted to electromagnetic radiation at least as energetic as X-rays, and to charged particles of similar energies. Neutrons also may induce ionization. 

Intense laser sources have been used to induce ionization or fluorescence of products in several kinds of photolytic experiments. Welge and his colleagues have used these sources to detect NO by multiphoton ionization (MPI) of the product. They have also used lasers that have been extended to the VUV region by various nonlinear mixing schemes as photoionization sources for mass spectrometric detection of reaction products. 

Characteristic trends in the fragmentation patterns of 1,4-benzodiazepines can be observed using ion-trap mass spectrometry (MS). For the l,4-benzodiazepin-2-one 15, ion fragmentation was largely dictated by the attached substituents, R1, Rz, R3, and R4 <2000RCM2061>. Using collision-induced ionization (CID) spectrometry, the C-3-unsubstituted analogues were shown to eliminate CO while the hydroxylated compounds predominantly... 

Extensive photoionization studies by Ding et al. (1987) have shown that there are essentially three different mechanisms responsible for the ionization of neutral heteroclusters of the type R Xm (where R = rare gas atoms and X = polyatomic molecule). Similar ionization mechanisms are also possible using electron-induced ionization studies. The various possibilities are summarized, as follows. 

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