	This is part of the clusters module
	It is only available if you configure PLUMED with ./configure –enable-modules=clusters . Furthermore, this feature is still being developed so take care when using it and report any problems on the mailing list.

Determine the atoms that are within a certain cutoff of the atoms in a cluster

ATOMS	the atoms that were used to calculate the matrix that was clustered
CLUSTERS	the label of the action that does the clustering
CLUSTER	( default=1 ) which cluster would you like to look at 1 is the largest cluster, 2 is the second largest, 3 is the the third largest and so on.

RCUT_SURF