Structure factor, determination

The coherent tunneling case is experimentally dealt with in spectroscopic studies. For example, the neutron-scattering structure factor determining the spectral line shape is... 

Plastics have the widest variety and range of mechanical properties of all materials (Figs. 1-8 and 7-1 and 7-2). They vary from basically soft to hard, rigid solids. Great many structural factors determine the nature of their mechanical behavior, such as whether a load occurs over the short term or the long... 

Fox, A.G., and Fisher, R.M. (1986) Accurate structure factor determination and electron charge distributions of binary cubic solid solutions, Phil. Mag. A, 53, 815-832. 

Hoier, R., Bakken, L.N., Marthinsen, K. and Holmestad, R. (1993) Structure factor determination in non-centrosymmetric crystals by a two-dimensional CBED-based parameter refinement method, Ultramicroscopy, 49, 159-170. 

Accurate structure factor determination using 100 keV synchrotron radiation... 

The classification of radical reactions carried out in this way makes it possible to observe empirically (on the basis of the parameter bre) the structural differences between the reactants within one class, to compare the classes and groups of reactions in terms of reactivity (in terms of the parameter Z>re or Ee0), and to identify the physical and structural factors determining the reactivities of groups and classes of reactants. 

A series of aggregation structures of bilayer forming azobenzene amphiphiles, CnAzoCmN+Br, both in single crystals and cast films was determined by the X-ray diffraction method and uv-visible absorption spectroscopy. From the relationship between chemical structures and their two-dimensional supramolecular structure, factors determining the molecular orientation in bilayer structure were discussed. Some unique properties based on two-dimensional molecular ordering were also discussed. 

Several other techniques, such as electron holography (Lichte, 1986) and convergent beam electron diffraction (CBED) have also been developed for structure analysis. CBED can provide information not only on the lattice parameters and the S5mimetry of crystals, but also accurate structure-factor amplitudes and phases (Hoier et al, 1993). Accurate structure factor determination by CBED can provide information on the location of valence electrons. However, it is more favourable for thick crystals (> 500 A) with small unit cells (< 10 A). Structure analysis by CBED has been summarized in two review articles (Spence, 1993 Tanaka, 1994). 

Quantitative measurement of the intensity for structure factor determination or for charge density measurements can be performed on CBED patterns [6] or from electron precession patterns. 

Rees B (1977) Data-processing and structure-factor determination. Isr J Chem 16 154-158... 

Polymers vary from liquids and soft rubbers to very hard and rigid solids. Many structural factors determine the nature of the mechanical behavior of such materials. In considering structure-property relationships, polymers may be classified into one of several regimes, shown in the volume-temperature plot (Fig. 23.1). 

Structural Factors Determining Knocking Characteristics of Pure Hydrocarbons... 

G. M. Lipkind, A. S. Shashkov, S. S. Mamyan, and N. K. Kochetkov, The nuclear Overhauser effect and structural factors determining the conformations of disaccharide glycosides, Carbohydr. Res., 181 (1988) 1-12. 

Table 6.6. The three-dimensional electron density distribution in the symmetrically independent part of the unit cell of LaNi4 85Sno,i5 calculated using the observed structure factors determined from Le Bail s extraction Table 6.4) and phase angles determined by the...

Considering the low Rp, the absence of new peaks on the second Fourier map, which may correspond to additional atoms, and the fact that the contents of the unit cell matches that established from the gravimetric density of the material, we conclude that all atoms in the unit cell of LaNi4,85Sno.i5 have been located. It makes no sense to proceed with the least squares refinement of atomic parameters using structure factors determined from Le Bail s extraction, and the refinement of the crystal structure should be completed using the Rietveld technique (see Chapter 7). The coordinates and possible distribution of atoms are listed in Table 6.8 and the crystal structure of the material is illustrated in Figure 6.14. 

Table 6.27. The three-dimensional nuclear density distribution in the symmetrically independent part of the unit cell of CeRhGea calculated using the observed structure factors determined from Le Bail s extraction Table 6.23) and phase angles determined by Ge in 4(b) with z = 0.000, Ge in 2(a) with z = 0.355, Ce in 2(a) with z = 0.754, and Rh in 2(a) with z = 0.113 in the space group I4mm (Rp = 16.3 %). ...

The array of the individual structure factors determined from Le Bail s full pattern decomposition was processed using WinCSD (see footnote No. 4 on page 515) and, according to a combined figure of merit, one of the possible solutions was notably better than the others. The subsequently calculated E-map is listed in Table 6.31. 

Thirteen structural parameters may seem excessive, but these parameters are general, they incorporate the very complex structural factors determining Tg, and they obviate the need for group contributions. Even with a vastly larger number of group contributions, the Tg of many new polymers cannot be estimated because of the lack of some of the group contributions. 

What are the main structural factors determining the boiling point of an inorganic compound (See Pauling, Nature of the Chemical Bond, Chapter 2.)... 

In the author s opinion, this approach is not without shortcomings such as the necessity of obtaining the values of the partial 1,2-shift rate constants from the overall values of the rate constants of rearrangement and the difficulty in identifying the structural factors determining the rate of rearrangement. 

As most often the structural factors determining biological activities are not directly known, multiparameter tables should be used together with a multivariate characterization approach. 

Sim] Anomalous small-angle X-ray scattering < 25 at% Fe, 2-41 at% Ni, annealed at 500°C. Structure factors determination... 

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