virtual double GetRadius() const
Return the floating point radius assigned to an atom. The default
value is 0.0. The ``radius'' property on an atom may be set using
the OEAtomBase::SetRadius
method. The radius property is
typically used to hold a Van der Waal's or ionic radius for a given
atom when passing an OEMolBase
to an algorithm requiring some
form of radii, such as a surface area calculation.