Strong Isotopic Effect in Phase II of Dense Solid Hydrogen and Deuterium

Abstract

Quantum nuclear zero-point motions in solid H${}_2$ and D${}_2$ under pressure are investigated at 80 K up to 160 GPa by first-principles path-integral molecular dynamics calculations. Molecular orientations are well-defined in phase II of D${}_2$, while solid H${}_2$ exhibits large and very asymmetric angular quantum fluctuations in this phase, with possible rotation in the (bc) plane, making it difficult to associate a well-identified single classical structure. The mechanism for the transition to phase III is also described. Existing structural data support this microscopic interpretation.

5 pages, 3 figures

References in corpus (1)

• A superconductor to superfluid phase transition in liquid metallic hydrogen

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