double OEGetBondiVdWRadius(unsigned int elemno)
Return the Van der Waals radius for a particular atomic number as
tabulated in A. Bondi, ``Van der Waals Volumes and Radii'', Journal
of Physical Chemistry, Vol. 68, No. 3, pp. 441, 1964. There are
several experimental values for Van der Waals radii (see also
OEGetPaulingVdWRadii
) and many additional values used in
molecular mechanics forcefields (including united-atom VdW radii),
so there is often no definitive notion of Van der Waals radius.