New hydrogen mixture exhibits different molecular interactions

New hydrogen mixture exhibits different molecular interactions

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A team of scientists led by Dr Ross Howie of the University of Edinburgh, combined hydrogen (H2) and deuterium (D2) to produce a new “Phase IV” material in which molecular interaction was found to be different than previously observed. The research study was published in the journal Physical Review Letters. In the Phase IV material, the hydrogen molecules displayed two different behaviors: one interacted strongly with the adjoining molecules, while the other bonded weakly with the neighboring molecules. This resulted in unique hexagonal atomic sheets similar to graphene. In electronic context, these layers behave like semimetals and semiconductors.

When producing the new hydrogen mixture, the scientists combined experiments and theoretical calculations to prevent segregation of the D2 and H2 molecules between weakly and strongly bounded layers. They mixed the H2 and D2 in varying concentrations and subjected them to room temperature under different pressures, ranging from about 2,000 times atmospheric pressure (.2 GPa) to about 2.7 million atmospheres (270 GPa). Raman spectroscopy was also used to validate the experiment. It was observed that the vibrational waves tend to exhibit Anderson localization when there is more than 1.9 million atmospheres. Anderson localization is a phenomenon wherein the disordered state affects atomic vibration waves and prevents their free propagation. Also, the degree of this localization not only depends on the concentration of D2 and H2, but also on the strong or weak bounded layers of the H2 and D2 molecules.