two-probe system can deal with the situation in which a cluster as a electrode?

[njuxyh]

hi,

i want to model the Ti-cluster-GNR-Ti-cluster as which in the reference http://pubs.acs.org/doi/abs/10.1021/nn401357p,see the geometry configuration.
and  i already know each electrode is a period system in ATK, but i do not know if a electrode is a cluster, atk can model the case?