Radius of the capped end of Nanotube

[Abe]

for nanotubes if the configuration(n,m) is known it is possible to calculate the radius of the nanotube from it.But if the ends of a give (n,m) is capped, How to calculate the radii of the capped end of the tube.

Because some papers report different configurations for the capped structure.

Whether the radii of the capped end nanotube is related to the (n,m) value of the nanotube, if yes how

[Anders Blom]

In general you can cap any nanotube, but the cap will not necessarily be a hemisphere and thus will not have a well-defined radius. There are however some famous combinations where the radius of the tube matches (closely) the radius of a fullerene. For example, a C60 "buckyball" matches well a (5,5) CNT.