Notes to Chapter Four

The facts noted in the four subsections of this chapter suggest that chemists ought to keep an open mind concerning the concept of chemical bonding. Useful as this concept is the field of organic chemistry, it becomes more and more meaningless and inadequate as we move toward inorganic, nonmetallic and, above all, metallic chemistry. 

The Table of Formula Masses (four decimal places) is convenient for selecting tentative, molecular formulas, and fragments on the basis of unit-mass peaks. Note that in the first paragraph of the Introduction to Chapter 7, there is the statement Go for the molecular formula. ... 

Of course, the details of the gain spectra depend on the dimensionality of the active material (bulk, quantum well, etc.) and on the details of the band structure. For such detailed calculations we refer to Chapter A6 of this volume. However, it is important to note that due to the specific band structure of the nitrides, the carrier densities needed to achieve inversion and optical gain are very large compared to other m-V semiconductors. In particular, both the electron effective mass (nw = 0.22 [7]) as well as the hole effective mass (mi, 2.0 [8-10]) are three- to four-fold larger than in GaAs. For the same reason, however, the maximum gain obtainable from nitride structures is also larger. 

PdO. In this structure also (which is that of PtS) the metal atoms form four coplanar bonds the coordination of 0 is tetrahedral (Fig. 12.4). As noted in Chapter 1 the bond angles represent a compromise between the ideal values of 90° and 109 ° due to purely geometrical factors. CuO has a less symmetrical variant of the PtS structure, and it is interesting that whereas CuO has the less symmetrical... 

The coupling constant for the methylene-hydroxyl interaction is found to be (CH2, OH) = ca. 5 Hz. The methyl triplet is found to have a different coupling constant, (CH3, CH2) = ca. 7 Hz., for the methylene-methyl coupling. The methylene protons are not split into a quintet by their four neighbors, as the couphng constants for hydroxyl-methylene and methyl-methylene are different. As noted in Chapter 5, the n -t 1 Rule does not apply in such an instance each interaction occurs independently of the other, and a graphical analysis is required to approximate the correct pattern. 

As noted above (Chapter 3), the Nine Elixirs has come down to us in two versions, one contained in the first chapter of the Jiudan jingjue and the other included in the Scripture of the Liquid Pearl in Nine Cycles and of the Nine Elixirs of the Divine Immortals (Jiuzhuan liuzhu shenxian jiudan jing dllfSitSW flljAfTIM CT 952.). Besides the Scripture itself, four other entirely or partially extant wor s have the Nine Elixirs as their main subject ... 

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