The Alkali Elements at Extreme Compressions: Static and Dynamic Compression Techniques
- Event time: 1:00pm
- Event date: 23rd January 2012
- Speaker: Emma McBride (Formerly School of Physics & Astronomy, University of Edinburgh)
- Location: Room 2511, James Clerk Maxwell Building (JCMB) James Clerk Maxwell Building Peter Guthrie Tait Road Edinburgh EH9 3FD GB
The alkali elements have been a "hot" topic in high pressure research for the last decade. Nearly-free electron metals at ambient pressure, they show a remarkable departure from this "simple" behaviour with pressure. Complex, low-symmetry, open-packed structures have been observed in Li, Na, K, Rb and Cs. Anomalous melting, where the gradient of the melting curve (dT/dP) becomes negative over large pressure regions, has been observed in Rb, Cs, Na and Li, but had not been observed in K. We have used static compression techniques (diamond anvil cell) to re-examine the melting curve of K.
Although a vital tool in high-pressure research the pressure and temperature conditions achieved with the diamond anvil cell technique have not typically exceeded 400 GPa and several thousand Kelvin, leaving many exotic states of matter, including those in the alkali metals, tantalizingly out of reach. A method to get beyond this limit is by using extremely powerful lasers to ramp- or shock- wave compress materials. Here recent data on the ramp- and shock-wave compression of Na will be presented.
This is a weekly series of informal talks given primarily by members of the soft condensed matter and statistical mechanics groups, but is also open to members of other groups and external visitors. The aim of the series is to promote discussion and learning of various topics at a level suitable to the broad background of the group. Everyone is welcome to attend..