Ions, spectroscopy

Cordermann R R and Lineberger W C 1979 Negative ion spectroscopy Annual Review of Physical Chemistry ed B S Rabinovitch, J M Schurr and FI L Strauss (Palo Alto, CA Annual Reviews)... 

Johnson M A and Lineberger W C 1988 Puised methods for ciuster ion spectroscopy Techniques for the Study of Ion-Molecule Reactions ed J M Farrar and W H Saunders Jr (New York Wiiey)... 

Czanderna A Wand Flercules D M (ed) 1991 Ion Spectroscopies for Surface Analysis (New York Plenum)... 

Shoji F, Kashihara K, Sumitomo K and Oura K 1991 Low-energy recoil-ion spectroscopy studies of hydrogen adsorption on Si(100)-2 x i surfaces Surf. Sc/. 242 422-7... 

Occasionally, especially in the developmental phase of catalyst research, it is necessary to determine the oxidation state, exact location, and dispersion of various elements in the catalyst. Eor these studies, either transmission electron microscopy (TEM) or scanning electron microscopy (SEM) combined with various high vacuum x-ray, electron, and ion spectroscopies are used routinely. 

The material evaporated by the laser pulse is representative of the composition of the solid, however the ion signals that are actually measured by the mass spectrometer must be interpreted in the light of different ionization efficiencies. A comprehensive model for ion formation from solids under typical LIMS conditions does not exist, but we are able to estimate that under high laser irradiance conditions (>10 W/cm ) the detection limits vary from approximately 1 ppm atomic for easily ionized elements (such as the alkalis, in positive-ion spectroscopy, or the halogens, in negative-ion spectroscopy) to 100—200 ppm atomic for elements with poor ion yields (for example, Zn or As). 

Fig. 3.57. Different experimental geometries for low energy ions spectroscopies.

The approach we have adopted for the d configuration began from the so-called strong-field limit. This is to be contrasted to the weak-field scheme that we describe in Section 3.7. In the strong-field approach, we consider the crystal-field splitting of the d orbitals first, and then recognize the effects of interelectron repulsion. The opposite order is adopted in the weak-field scheme. Before studying this alternative approach, however, we must review a little of the theory of free-ion spectroscopy... 

The present section is offered as a review of the jargon of the theory of free-ion spectroscopy with little in the way of any free-standing explanation. ... 

Molecular-level characterization of surface composition and stmcture can be obtained through a variety of electron and ion spectroscopies. The two-dimensional stmcture of surfaces and ordered arrays formed by adsorbates is revealed by low-energy electron drfiraction... 

Why are electron and ion spectroscopies generally surface-sensitive techniques when applied in the low-energy regime ... 

A second role for mass spectrometry in the investigation of reactive intermediates involves the nse of spectroscopy. Althongh an important nse of ion spectroscopy is the determination of thermochemical properties, including ionization energies (addition or removal of an electron), as in photoelectron or photodetachment spectroscopy, and bond dissociation energies in ions, as in photodissociation methods, additional spectroscopic data can also often be obtained, inclnding structural parameters such as frequencies and geometries. 

A.W. Czanderna and D. M. Hercules, Ion Spectroscopies for Surface Analysis, Plenum Press, New York, 1991. 

In spite of the continued interest in cross-conjugated polyenes ( dendralenes ), of which more than 100 are known307, surprisingly few of these have been investigated by PE or radical ion spectroscopy. ... 

D. Klapstein, J. P. Maier and L. Misev, in Molecular Ions Spectroscopy, Chemistry and Structure (Eds. T. A. Miller and V. Bondybey), North-Holland, Amsterdam, 1983. 

If reaction (2-13) follows reaction (2-12) instantaneously, the effect will not be noticeable in the H2 signal [12]. In spite of these limitations, we conclude that TPS with mass spectrometric detection is a highly useful technique for studying the sulfidation of hydrotreating catalysts. We shall return to the sulfidation of molybdenum oxides in the chapters on photoemission (Chapter 3), ion spectroscopy (Chapter 4), and in a case study on hydrodesulfurization catalysts in Chapter 9. 

In this chapter we describe briefly the physical phenomena, such as sputtering, scattering, neutralization and reionization, that are involved in ion spectroscopy. For a detailed description of the interactions of ions with solids we refer to the books by Feldman and Mayer [1], Benninghoven, Riidenauer and Werner [2], and Czandema and Hercules [3]. 

U. Boesl. Multiphoton Excitation and Mass-Selective Ion Detection for Neutral and Ion Spectroscopy. J. Phys. Chem., 95(1991) 2949-2962. 

The methodology of surface electrochemistry is at present sufficiently broad to perform molecular-level research as required by the standards of modern surface science (1). While ultra-high vacuum electron, atom, and ion spectroscopies connect electrochemistry and the state-of-the-art gas-phase surface science most directly (1-11), their application is appropriate for systems which can be transferred from solution to the vacuum environment without desorption or rearrangement. That this usually occurs has been verified by several groups (see ref. 11 for the recent discussion of this issue). However, for the characterization of weakly interacting interfacial species, the vacuum methods may not be able to provide information directly relevant to the surface composition of electrodes in contact with the electrolyte phase. In such a case, in situ methods are preferred. Such techniques are also unique for the nonelectro-chemical characterization of interfacial kinetics and for the measurements of surface concentrations of reagents involved in... 

Positive imaging techniques, 19 201 Positive ion spectroscopy, 24 107 Positive photochromism, 6 588 Positive photoresists, 20 280-281 Positive photosensitive polyimides,... 

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