Atomic ratios with density, variation

Figure 6. Variation of atomic ratios with density for several high volatile bituminous coals (a) H/C ratio (b) 0/C ratio.

For some time, it was known [159,160,390,405] that the depolarization of fluids composed of isotropic atoms or molecules is nonvanishing if the particle density is sufficiently high. The density-dependent depolarization of light by isotropic fluids is now understood to be caused by the anisotropy of the collision-induced polarizability increment of two or more interacting atoms or molecules [177, 178,376, 390]. Depolarization ratios are often expressed in terms of a virial series whose nth term accounts for the n-body interactions, with n = 2, 3. . . [161, 164, 165, 167, 170, 175]. Fluids composed of optically anisotropic molecules show a variation of the depolarization ratio with density that is understood as arising from the interplay of the permanent and induced anisotropies the anisotropy of the interaction potential also plays a role [161, 188]. The literature concerned with density-dependent depolarization of light is included in Section 1.2. By contrast, CILS spectroscopy is considered in Section 1.3. 

Mechanistic studies are often performed on binary alloys. Hf-Zr-binary alloys are excellent examples [118]. Because of the lan-thanoid contraction, both elements show an extraordinary chemical similarity. The atom radii are identical and hence both can substitute for each other easily. Both elements form stable passive films and so do all their alloys. The physical parameters of the oxides such as density, permittivity, and crystallinity show a continuous changeover with variation of the atomic ratio. 

Figures 6.37 and 6.38 show the variation of electrical properties as a function of the dopant content of ZnO films. Figure 6.37 shows the case of AP-CVD ZnO F with fluorine as dopant (here, the fluorine atomic fraction is considered as dopant content). Figure 6.38 shows the case of LP-CVD ZnO B with boron as dopant (here, the B2H6/DEZ ratio is considered as dopant content). The electrical properties taken into consideration are the conductivity a, the resistivity p, the mobility //, and the free carrier density N.

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