Figure 3.

Density slices from (a) a binary model mask and (b) the corresponding Gaussian model mask (the polynomial model mask is similar and is not shown) derived from test model 1exr. The coloring scheme is from red (zero density) through white (0.5 density level) to blue (1.0 density level). Below each density slice is a one-dimensional representation of the mask for each case, given a single atom at the origin. The distance from the atom in Å is given on the x axis and the y axis depicts the relative electron density of the mask. In (d), the Gaussian model (A = 11.5 Å, σ = 0.55 times the van der Waals radius) is shown in blue and the polynomial model (a set to the van der Waals radius, w = 0.8 Å) is shown in magenta given an atom with a van der Waals radius of 1.75 Å.