Hydrogen parameters

The intensity curves I, II, III, and IV of Fig. 4 are calculated for coplanar trans models with C-H = 1.06 A., the angle H - C=C = 115°, and the angle H—C—H = 109.5°. Although these hydrogen parameters are so chosen as to agree as well as possible with minor peaks of the radial distribution function, no great reliance can be placed on them, and indeed it is likely that for this molecule the C-H bond distance is 1.09 A. The models have the following additional parameters... 

The model system for these calculations is carboxy-myoglobin starting from the X-ray coordinates (19). The polar hydrogen parameter set PARAM19 (20) was used for all calculations. In this representation there are 1532 atoms. It is not expected that the results of this work would change substantially if a different protein or if a different parameter set were used. 

This contribution Is concerned with the magnetic and Mossbauer characterization of (a) Fe/zeollte (mordenlte) systems, and that of (b) Fe and/or Ru on boron-doped carbon substrates. Some correlations between the characterization and CO hydrogenation parameters will be pointed out. Because of limitations of space, we shall present salient features of these Investigations. At the outset. It would be befitting to present a succinct background on the basic principles of magnetic and Mossbauer characterization. 

The use of sp data is often imperative for an accurate ed analysis. Symmetry, force constants, and rotational constants determined (or estimated) by sp are helpful in the ed analysis (Figure 3), and closely spaced distances and hydrogen parameters, which are often difficult to determine by ed data alone, may sometimes be determined with reasonable accuracy. For example, the multiple possibilities of the Se02F2 structures mentioned by Hedberg may be solved if rotational constants can be taken into the analysis. 

Local Csv symmetry for the CF3 group was assumed. The hydrogen parameters S-H, angle S-S-H and r(S-S) were set to the corresponding valnes in H2S2. 

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