Prof. Eugene Gregoryanz [University of Edinburgh, UK]

Title:
The Melting Curves of Elements at Megabar Pressures

Speaker:
Prof. Eugene Gregoryanz (from Edinburgh)

Time:
14:00 – 16:00, July 4, 2014

Place:
Conference Room, BLDG 3 FL2, HPSTAR (Shanghai)

Abstract：
As the simplest and the most widely distributed element in the universe, hydrogen has similar atom structure with alkali metals, such as Na and Li. Some unusual properties can be detected when their atom shells are compressed by high pressure. Studies of Prof. Eugene indicated the melting curve of Na sloped down in 30 GPa, and the sample melted in room temperature when compression went to 120 GPa. It can be inferred that some strange structural changes also could be seen in hydrogen, which may help to probe the structural information and electronic transitions of metallic hydrogen. In the presentation, Prof. Eugene will present their results covering the melting curves of the group elements including Na, Li and hydrogen. Interestingly, although very different physics governs the behavior of the atomic metallic alkali metals and insulating molecular dense hydrogen, their phase diagrams appear strikingly similar. Their phase diagrams have negative melting slopes, very well defined minima and clustering of the complex solid phases around the minima. The principal detection methods are high-pressure Raman spectra and synchrotron radiation X-ray diffraction. In addition, he will demonstrate the versatility of the diamond anvil cell techniques in the static high-pressure experiment.

Biography of the speaker:
Prof. Eugene Gregoryanz is a Professor of School of Physics and Astronomy at University of Edinburgh (UK) since 2012. He joined Institute of Physics of Russian Academy of Science as a research scientist in 1989. He was a Senior Research Scientist at Geophysical Laboratory of Carnegie Institution of Washington. In 2005, he was invited as a Professor of Laboratoire de Mineralogie-Crystallographie de in Universitй de Paris VI. As an outstanding scientist in high-pressure, he has 80+ publications which include 30+ papers in such journals as Nature, Science, Phys. Rev. Letters and PNAS.