Evan H. Abramson
Research Associate Professor
Fax: 206-543-0489 (shared)
Interests: Learning how the properties of fluids change at high pressures and temperatures, with an eye to the development of empirical, predictive associations among such properties.
Research Groups: Mineral Physics
Little information is available concerning the thermodynamic properties of fluids above pressures of ~1 GPa (10 kbar) and practically no information on their transport properties (i.e., chemical diffusivity, thermal diffusivity, shear viscosity). For the most part, this situation is a result of the lack of techniques suitable to the exigencies of the high-pressure, diamond-anvil cell and also to the necessity, for all but a very few substances, of working at elevated temperatures.
In the last several years, our group has pioneered the application of transient optical gratings to the measurement both of speed of sound (a thermodynamic function) and thermal diffusivity within the diamond-anvil cell. These methods are being constantly improved and are being applied to a broad sampling of simple fluids, from hydrogen-bonded water and ammonia, to the noble gases, up to the pressures, associated densities and temperatures readily accessible in the diamond-anvil cell. Several new possibilities for the measurement both of viscosity and mass diffusion are also being explored. Our goal is to acquire data which can form the basis for an understanding of the basic properties of fluids under conditions of high pressure and density.
In addition to fluids, we have used some of the same techniques to study simple solids such as (crystalline) argon and oxygen, metals such as iron and tantalum, and silicate minerals.
Here's a figure which shows a few of the interesting phenomena which occur at high pressures, both from a geophysical and general perspective.
Here's a schematic of a diamond-anvil cell and a photograph taken through the backs of the diamonds. In the photo the pink, vaguely rectangular object is a single crystal of oxygen held at room temperature and 57 kbar, floating in supercritical fluid oxygen. The adjacent, colorless crystal is a piece of ruby, our pressure gauge. A platinum sphere, used to measure the viscosity of the fluid, is visible as a round, dark object. Several of the diamond facets can be seen around the perimeter.
Abramson,E.H., "Melting Curves of Argon and Methane", High Pressure Research, v.31, 549-554 (2011)Abramson, E.H., "Speeds of Sound in Fluid Ammonia to 3.8 GPa and 680K", J. Chem. Eng. Data v.53, pp.1986-87 (2008)Abramson,E.H. and West-Foyle, H., "Viscosity of Nitrogen Measured to Pressures of 7 GPa and Temperatures of 573K, Phys. Rev. E, v.77, 041202-1-5 (2008)Abramson,E.H., "Viscosity of Water Measured to Pressures of 6 GPa and Temperatures of 300C, Phys. Rev. E, v.76, 051203-1-6 (2007)Abramson, E.H. and Brown,J.M., "Equation of State of Water Based on Speeds of Sound Measured in the Diamond-Anvil Cell", Geochim. Cosmochim. Acta, v.68, pp. 1827-1835 (2004)Abramson,E.H., Brown,J.M. and Slutsky,L.J.,"The Thermal Diffusivity of Water at High Pressures and Temperatures", J. Chem. Phys., v.115, 10461-3 (2001)