Bunches of red oxygens and white hydrogens show the probability
that a water molecule at certain distance *r* from the fixed
(blue and yellow) molecule will have given relative position and
orientation. The animation is thus an attempt to
visualize the **full pair correlation function**.
This function is six-dimensional: one
distance *r* and five angular variables. We have measured this
function during a 300 ps simulation of 500 TIP4P water molecules at
*T*=25^{o}C and ambient density.
The histograms were
taken by 15^{o} in each angular variable (with the exception
of regions close to the poles). The *r*-coordinate is
identified with time, i.e., each frame corresponds to a selected
distance (shown in red in the graph of the O-O pair correlation
function). For this distance, one molecule from the pair is fixed, and
around it 8000 positions of water molecules with highest probability
are drawn with diameters proportional to the probability.
See also the water page.