Superfluid Response of Parahydrogen Clusters in Superfluid 4He

First-principle computer simulations yield evidence of a finite superfluid response at low temperature of a parahydrogen cluster of 15 molecules in bulk superfluid 4 He. The superfluid fraction is worth similar to 44% at T = 0.25 K, growing to about similar to 66% at T = 0.15 K, i.e., it is substantially reduced compared to that of the same cluster in vacuo, due to higher molecular localization. The implications of these findings on the interpretation of experiments with linear molecules embedded in parahydrogen clusters immersed in superfluid helium are discussed.