Angular parameters coordination geometry

The SHAPES force field" has been implemented in CHARMM and used to examine the structures of several square planar rhodium complexes. This force field is based on angular overlap considerations and treats angular distortions for a variety of geometries. Spherical internal coordinates and Fourier potential functions form the basis for the description of these molecular shapes. The parameters for this force field were derived from normal coordinate analysis, ab initio calculations, and structure-based optimizations. The average rms deviation for bond lengths was 0.026 A, and the average rms deviation for bond angles was 3.2°. 

Additionally, in Laue geometry only cell ratios can be determined from the angular coordinates of spots. The absolute cell parameters therefore have to be provided from a monochromatic study. However, if the intensities of spots are also considered, then there appears to be scope to solve the problem by using knowledge of Amin (section 7.2.3) and the bromine K edge in the photographic film as wavelength markers. 

Tabie 2. AOM parameters and angular variables for hexa-coordinated complexes where the first coordination spheres [MAg] (A = N, O, Cl) show an octahedral or trigonally distorted geometry. The lower symmetries may be induced, for example, by the chelate geometry or by impacts due to the crystal lattice. The symmetry of the LF potential may be reduced if non-isotropic rr-bonding is apparent The actual structure of the [MAj] entity is very near to an octahedron. For planar chelates ip is not independent from 6 and

complexes investigated in this contribution... 

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