Chemistry Reference
In-Depth Information
Fig. 7 Direct-space difference density maps for
Terbogrel
(c) in the plane of the guanidine
fragment. (a)
r
C
r
AVE
, where
r
AVE
is the average density built from the SPA data bank,
(b) the same map obtained after refinement of the populations of the average databank density. The
theoretical density was calculated at the B3LYP/cc-pVTZ level.
Contour lines
are drawn at
0.05 e
˚
3
.
Solid
,
dashed
, and
dotted lines
are positive, zero, and negative, respectively
data yields an
R
-value of 2.02%, which decreases to 1.65% after the refinement of
the SPA populations.
10 Summary
As demonstrated by the
glycine
simulation, the unrestricted SPA (
L
4) model
provides an adequate representation of the MO density and the corresponding error-
free static structure factors. The study also implies that the application of bonded-
atom RDFs is necessary to reach the accuracy commonly claimed for experimental
pseudoatom densities. However, the accuracy reachable for the local topological
figures seems to be severely limited by the level of expansion. This could partially
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