Densities, various

Cokes with binder pitches Polycrystalline graphite blocks Various densities, various degrees of orientation... 

Inasmuch as the phases dominate the appearance of the electron density map, errors in the phases will make the map much more difficult to interpret. Unfortunately, the initial phases obtained from the methods outlined above always contain errors. In experimental methods, very small differences in amplitudes are measured and the resulting phases are the statistical best estimates This does not mean they are right they may not yield the most interpretable map. Even before constructing a model to interpret the density, various forms of density modification are used to improve the map. 

The main source of the error was attributed to a residual self-correlation energy (the electron is treated as a continuous fluid and the correlation energy is calculated between different parts of this density ). Various fixes have been attempted . That of Stoll et al. involves using the LSD approximation ... 

The characteristics for a recycled polyol presented in Table 20.1 have a large range of values due to the fact that the qualities of the rigid PU wastes used are not consistent (the rigid PU foam wastes are made in various densities, various formulations, some foams are degraded and so on). 

If the various terms could be evaluated and a suitable calibration found, the isomer shift could be used to determine electron densities. Various values for SR/R have been given, based on estimated values of the isomer shift for ions of particular electronic configuration (e.g., Sn, 4d ) and values of electron densities calculated from the Fermi-Segr formula or from SCF wave functions (14, 19, 78, 86, 101, 124,... 

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