## Rotational fluctuation of molecules in quantum clusters. II. Molecular rotation and superfluidity in OCS-doped helium-4 clusters

In this paper, quantum fluctuations of a carbonyl sulfide molecule in helium-4 clusters are studied as a function of cluster size N in a small-to-large size regime (2{<=}N{<=}64). The molecular rotation of the dopant shows nonmonotonic size dependence in the range of 10{<=}N{<=}20, reflecting the density distribution of the helium atoms around the molecule. The size dependence on the rotational constant shows a plateau for N{>=}20, which is larger than the experimental nanodroplet value. Superfluid response of the doped cluster is found to show remarkable anisotropy especially for N{<=}20. The superfluid fraction regarding the axis perpendicular to the molecular axismore »