As was the case for XPS, to understand the correct use of sensitivity factors in AES it is necessary to consider briefly the origin of the various terms that give rise to the Auger intensity in the electron spectrum. The intensity of emission of Auger electrons originating from a particular electronic transition in a uniformly illuminated specimen of element a is [Pg.195]

There are many technical terms, qualifications, and fine points which could not be gone into here. The reader will gather that the correct use of the AIM method can be tricky, and one is urged to consult review papers and books for more details, and to proceed with caution, especially if one is sensitive to criticism. [Pg.359]

It is a common, but illogical, practice to refer to this unit as a wave number correctly used, the term wave number refers to the physical quantity 1/Avac, and not to the unit of this quantity. [Pg.321]

This expression can be used to describe both pore and solid diffusion so long as the driving force is expressed in terms of the appropriate concentrations. Although the driving force should be more correctly expressed in terms of chemical potentials, Eq. (16-63) provides a qualitatively and quantitatively correct representation of adsorption systems so long as the diffusivity is allowed to be a function of the adsorbate concentration. The diffusivity will be constant only for a thermodynamically ideal system, which is only an adequate approximation for a limited number of adsorption systems. [Pg.1510]

Another reminder is to watch out for the term stereoisomer used by itself In many places and in many textbooks this term is used in place of the term configurational stereoisomer. (Recall that configurational stereoisomers are the E/Z, cis/trans, R/S, D/L, +/- enantiomers, diastereomers, etc. that we have been working with in this ChemActivity.) The strictly correct use of the term stereoisomer includes all stereoisomers. That is, both configurational stereoisomers and conformational stereoisomers (conformers—covered in ChemActivity 6A). [Pg.173]

In an attempt to close the non-constructive controversy, Boure [23] claims that both forms of the pressure terms are acceptable. The occurrence of complex roots in the momentum equations is not related to the correct use of the pressure terms, but is primarily a problem of mathematical form of the constitutive terms. [Pg.487]

We have seen, particularly in the discussion of covalent crystals in terms of pseudopotentials, the importance of recognizing which matrix elements or effects are dominant and which should be treated as corrections afterward. This is also true in transition-metal systems, and different effects are dominant in different transition-metal systems thus the correct ordering of terms is of foremost importance. For many transition-metal systems, we find that band calculations, particularly those by L. F. Mattheiss, provide an invaluable guide to electronic structure. Mattheiss uses the Augmented Plane Wave method (APW method), which is analogous to the OPW method discussed in Appendix D. [Pg.537]

After selection of descriptors/NN training, the best networks were applied to the prediction of 259 chemical shifts from 31 molecules (prediction set), which were not used for training. The mean absolute error obtained for the whole prediction set was 0.25 ppm, and for 90% of the cases the mean absolute error was 0.19 ppm. Some stereochemical effects could be correctly predicted. In terms of speed, the neural network method is very fast - the whole process to predict the NMR shifts of 30 protons in a molecule with 56 atoms, starting from an MDL Molfile, took less than 2 s on a common workstation. [Pg.527]

The first application of mathematics to chemistry deals with various physical quantities that have numerical values. In this chapter, we introduce the correct use of numerical values to represent measured physical quantities and the use of numerical mathematics to calculate values of other quantities. Such values generally consist of a number and a unit of measurement, and both parts of the value must be manipulated correctly. We introduce the use of significant digits to communicate the probable accuracy of the measured value. We also review the factor-label method, which is a routine method of expressing a measured quantity in terms of a different unit of measurement. [Pg.1]

The other resins, which cure hy a free-radical chain-growth mechanism, also have a low-molecular-weight douhle-hond functional species dissolved in a solvent comonomer but, since these species are not polyesters, they cannot be termed alkyds. The term oligomers is used to describe them instead, although it is not a strictly correct use of this term, since the species are not always a multiplicity of repeat units. [Pg.428]

The intrinsic consequences of such strong activation of the carboxy group toward aminolysis are (1) the increased acidity of the C -proton which favors enolization giving 16 and (2) the facile ring closure of the carboxy-activated amino acid or peptide component to oxazol-5(4//)-ones 17 by base catalysis. Both mechanisms lead to loss of stereochemical integrity, i.e. racemization or epimerization as illustrated in Schemes 6 and (for the correct use of the terms racemization or epimerization see Vol. E 22b, Section 7.4). [Pg.22]

Fhe van der Waals and electrostatic interactions between atoms separated by three bonds (i.c. the 1,4 atoms) are often treated differently from other non-bonded interactions. The interaction between such atoms contributes to the rotational barrier about the central bond, in conjunction with the torsional potential. These 1,4 non-bonded interactions are often scaled down by an empirical factor for example, a factor of 2.0 is suggested for both the electrostatic and van der Waals terms in the 1984 AMBER force field (a scale factor of 1/1.2 is used for the electrostatic terms in the 1995 AMBER force field). There are several reasons why one would wish to scale the 1,4 interactions. The error associated wilh the use of an repulsion term (which is too steep compared with the more correct exponential term) would be most significant for 1,4 atoms. In addition, when two 1,4 [Pg.229]

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