Atomic-Scale Quantum Solvation Structure in Superfluid Helium-4 Clusters

The local superfluid density around a molecule embedded in a ⁴HeN cluster at low temperatures is analyzed using the path-integral Monte Carlo method. The molecular interaction induces a local nonsuperfluid component within a quantum solvation shell whose size is determined by the range of the molecule-helium interaction, and also introduces an anisotropic layering of the superfluid density around the molecule. We show that a local quantum hydrodynamic analysis is internally consistent for $N>50$, and can be used to calculate effective rotational constants for molecular dopants in superfluid helium.