Synopsis

Ordering in hydrogen under high pressure

Physics 3, s18
Molecular dynamics studies indicate a new phase of liquid hydrogen under high pressure.
Illustration: I. Tamblyn et al., Phys. Rev. Lett. (2010).

The behavior of hydrogen under pressure affects fields ranging from condensed matter physics to astrophysics. Compressed liquid hydrogen exhibits a molecular-to-atomic transition. However, despite several experiments, the theoretical debate on the nature of this transition, in particular whether it is a continuous or discontinuous (first-order) transition, has not yet been settled.

In an article in Physical Review Letters, Isaac Tamblyn and Stanimir Bonev of Dalhousie University in Nova Scotia, Canada, employ molecular dynamics to map the phase diagram of dense hydrogen over a large range of temperatures and pressures. Their findings suggest an unreported phase in the liquid with short-ranged orientational order, resulting from a transition that they predict should occur in the liquid above 100GPa. This new phase may explain certain characteristics of the molecular-to-atomic transition, the shape of the melting line, as well as the structure of hydrogen mixtures. The authors argue that a first-order transition is likely, and the new insight provided should spur future experimental work. – Sami Mitra


Subject Areas

Fluid Dynamics

Related Articles

Ocean Measurements Detect Conditions for Giant Waves
Fluid Dynamics

Ocean Measurements Detect Conditions for Giant Waves

Observations of the Southern Ocean show that wind can produce the surface states needed to generate rare “rogue” waves. Read More »

A Supernova Remnant Shaped by Vortices
Fluid Dynamics

A Supernova Remnant Shaped by Vortices

The clumpy structure of a ring of gas ejected by the progenitor star of the supernova 1987A could have formed when vortices in the gas interacted. Read More »

Prizes for Videos Featuring Mickey Mouse and Laptop Cables
Fluid Dynamics

Prizes for Videos Featuring Mickey Mouse and Laptop Cables

The winners of the third annual “Gallery of Soft Matter” competition included posters portraying robotic leaves and cannibalizing droplets and a video with what might be Steamboat Willie’s first appearance at the APS March Meeting. Read More »

More Articles