Phase Separation in Cold Para-H_{2} D_{2} Clusters.

Abstract

Low temperature phase separation in mixtures of ^{3}He and ^{4}He isotopes is a unique property of quantum fluids. Hydrogen has long been considered as another potential quantum liquid and has been predicted to be superfluid at T≤1 K, well below freezing temperature of ≈14 K. Phase separation has also been predicted in mixtures of para-H_{2} and D_{2} at temperatures ≤3 K. To defer the freezing, we produced clusters containing para-H_{2} and D_{2} at an estimated temperature of ≈2 K whose state was studied by vibrational Raman spectroscopy. The results indicate that the clusters are liquid and show the phase separation of the isotopes. The phase separation is further corroborated by the quantum molecular dynamics simulation.