Argonne Scientists Use Unique Diamond Anvils To View Oxide Glass Structures Under Pressure

Researchers at the U.S. Department of Energy's Argonne National Laboratory have used a uniquely-constructed perforated diamond cell to investigate oxide glass structures at high pressures in unprecedented detail.

Argonne physicist Chris Benmore and postdoctoral appointee Qiang Mei, along with colleagues at the University of Arizona, used microscopic laser-perforated diamond anvil cells to generate pressures of up to 32 gigapascals (GPa) – roughly one-tenth the pressure at the center of the Earth. By "squashing" vitreous (glassy) arsenic oxide samples between the anvils, the researchers were able to determine the mechanism behind the structure's atypical behavior under high-pressure.

This research may have far-reaching affects in the geophysical sciences, Benmore said, because oxide glasses and liquids represent a significant percentage of the materials that make up the Earth. For example, knowing the atomic structure of oxide materials at high pressures may give scientists a window on the behaviors of magma during the formation of the early Earth and moon. "We now have a technique where we can look a lot of different silicate glasses that are relevant to the Earth's process and at the complex behaviors of the melts that formed the Earth’s mantle," he said.

During their investigation, Benmore and Mei noticed that if arsenic oxide was subjected to high pressures the material underwent an unusual transformation at about 20 GPa, as the color of the compound changed from transparent to red. However, they did not know the atomic cause for this behavior.

By performing x-ray pair distribution function experiments at Argonne's Advanced Photon Source (APS), however, Benmore and Mei were able to see the atomic reconfiguration that produced the color change. Arsenic oxide, at normal pressures, typically exists in isolated molecular "cages" in which four arsenic atoms are surrounded by three oxygen atoms apiece – each of the six oxygen atoms is bounded to two arsenic atoms. When the pressure rose above 20 GPa, however, many of these molecular cages collapsed, creating new isomers in which each arsenic atom was bonded to six oxygen atoms.

600450 Argonne Scientists Use Unique Diamond Anvils To View Oxide Glass Structures Under Pressure
Date: 10 November 2007

See more news about:

See more from these topics:

Others also read

When searching for a manufacturer, Andreozzi Architects, along with Heritage Greenhouse Builders, approached Solar Innovations® to take their design and build a completely custom configuration.
New Vancouver landmark features more than 240 panels of Goldray dichroic glass.
Working with the architects at JPRA and glass installer Harmon, Inc., W&W Glass professional designers and engineers provided Pilkington Planar™ point-supported structural glass systems.
Ground-breaking glass pavilion structure at Apple Park comprising a 41m diameter glass drum elegantly supporting a thin carbon fibre roof.
A mixed-use 162m high rise project in Abu Dhabi with a unique twisted diagrid design.
The luxury mall features 3 major skylights. Two of them are mirror image freeform systems whereas the third is of a conventional symmetric lens shape.

Add new comment