Superfluidity of helium-4 around a Mg₁₁ cluster

We present results for ⁴He solvation of a Mg₁₁ cluster obtained with path integral Monte Carlo simulations. Using a pair-wise additive model for the helium-cluster interaction, we calculate energies, ⁴He densities and the superfluid response of ⁴He to a rotation of the Mg₁₁ cluster which has symmetric top symmetry. We find a significant superfluid fraction in the first ⁴He solvation layer around both axes of the cluster well before ⁴He covers the whole cluster. Based on the superfluid fraction, we estimate that Mg₁₁ in a large ⁴He nanodroplet would have an effective rotational constant between 60% and 70% of the gas phase rotational constant for rotation about the axis with larger moment of inertia. The dependence of the effective rotational constants on ⁴He cluster size N is similar to that of previously studied molecules with much larger gas phase rotational constants, with an initial decrease and a turn-around (at N = 13) when part of the ⁴He density becomes superfluid.