Minimizations, geometry

Table 10.1 Comparison of the number of steps required to minimize geometries using various coordinate systems ...

Table 10.3 Comparison of the number of steps required to minimize geometries (QN with RFO algorithm) using a unit matrix, empirically derived Hessian, and analytic Hessian for the initial Hessian followed by Hessian updating and using all analytic Hessians ...

Dist is the S -O distances (in A) and Angle is the planarity of the SCxC=0 motif (in degrees). Values are shown for the CSD crystal structure conformation and the minimized geometries for each of the methods. RMSD values (in A) are shown with respect to CSD structures. 

Figure 17 Stereoviews of the MMFF-minimized geometries of (a) 54 and (b) 56. Color code C, gray H, white O, red.

Of special interest are the eneigy barriers for given reactions, and in principle, calculation of the potential eneigy surfaces can provide these quantities. In practice, the majority of studies report one-point calculations on SCF-minimized geometries. Generally, calculations for gas-phase Sj 2 reactions use the model dqncted for the identity reaction ... 

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