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     COLLOQUIUM OF THE COMPUTATIONAL MATERIALS SCIENCE CENTER
AND THE SCHOOL OF PHYSICS, ASTRONOMY, & COMPUTATIONAL SCIENCES
                            (CSI 898-Sec 001)
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High Pressure: A New Dimension in the 21st Century Physical Sciences
                          Ho-kwang (David) Mao
Geophysical Laboratory, Carnegie Institution of Science, Washington DC

Pressure has long been recognized as a fundamental thermodynamic variable but
was previously limited by the available pressure vessels and probes. The
development of megabar diamond-anvil cells and a battery of associated
in-laboratory and synchrotron techniques at the turn of the millennium have
opened a vast new window. With the addition of the pressure dimension, we are
facing a brave new world with an order of magnitude more materials to be
discovered than all that have been explored at ambient pressure. 
Pressure drastically and categorically alters all elastic, electronic,
magnetic, structural and chemical properties, and pushes materials across
conventional barriers between insulators and superconductors, amorphous and
crystalline solids, ionic and covalent compounds, vigorously reactive and
inert chemicals, etc. In the process, it reveals surprising high-pressure
physics and chemistry and create novel materials. Exciting examples of
pressure-induced phenomena include intermetallic compound-alloy transitions
due to 4f electron delocalization, magnetic collapse in 3d transition
elements, complication of "simple electron gas" metals, and synthesis of
superhard amorphous carbon allotrope.  They illustrate the high-pressure
research as a new dimension in basic science as well as materials
applications. 

In nature, high pressures are generated inside the Earth and celestial bodies;
their interior processes, dynamics and formation are dictated by pressures.
Investigations with new-generation high-pressure probes are still at the
reconnaissance stage, but they have already shown profound impact on our
understanding the geochemistry of the deep mantle, the geodynamics at the
core-mantle boundary, the whole Earth water cycle, and the physics and
chemistry of planetary ices and gases.
 
                          December 10, 2012
                               4:30 pm
                    Room 301, Research I, Fairfax Campus

Refreshments will be served at 4:15 PM.
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Find the schedule at http://www.cmasc.gmu.edu/seminars.htm