IUCr Congress,
Geneva, 10. 8. 2002, Microsymposium M46
Structures and
Phase Transitions at High Pressure
(John Loveday, Serge Desgreniers Chairs)
Eugene Gregoryanz (Laboratoire de Minéralogie-Cristallographie de
Paris, Université Pierre et Marie Curie) described recent work on
the high pressure phase diagram of nitrogen. Over the past 2 years he and
co-workers at the Geophysical Laboratory of the Carnegie Institution of Washington
have discovered remarkable complexity in the megabar region including the
first evidence for the long-sought after non-molecular phase.
Jiuhua Chen (State University of New York at Stonybrook) described
a translating image plate detector and its use for real time kinetic studies
of olivine to spinel phase transition.
Pamela McGregor (University of Edinburgh) talked about her thesis work on
high-pressure structures of alcohols illustrating the structural complexity
which can now be handled at high pressure and the remarkable range of conformations
which the pressure variable can produce.
Simon Redfern (Cambridge University) described the development of a high-temperature/high-pressure
cell for neutron diffraction and recent experiments in structural studies
of hydrous minerals and of order-disorder phase transitions.
Neil Ashcroft (Cornell University) explored the implications of the complex
structures recently discovered in elemental metals at high pressure. These
high density metallic systems have a very different balance of
length-scales from that which operates in ''normal'' metals at ambient pressure
and offer new insight into the general problem of electrons in metals.
Taken as a whole, this lively and well-attended session illustrated well
the activity and diverse range of work going on in this important field.
John Loveday and Serge Desgreniers (Session Chairs)