| Research Abstract |
Our new techniques for studying the structure of liquids at high pressures make it possible to measure the structural changes in (1) elemental liquids with relatively low temperatures, such as liquid Te, liquid Si, and liquid Ge, up to above 20 GPa and (2) silicate melts, such as MgSiO_3 melt and CaSiO_3 melt, up to 6 GPa. Our paper that reports results of (2) in detail may be the first paper of this research field published in an international journal.The abstract of the paper is "We have developed synchrotron X-ray diffraction techniques for studying the structure of silicate melts and have applied them to measuring the structures of MgSiO_3 and CaSiO_3 melts up to 6 GPa. In both melts, it appears that the changes in the local structure around the divalent ions and in the network structure of SiO_4 tetrahedra are the dominant compression mechanisms while a change in the local structure around the Si ion is a secondary mechanism up to at least 6 GPa. The structural changes appear to be larger in CaSiO_3 melt than in MgSiO_3 melt, especially in the vicinity of ambient pressure. These results are consistent with available experimental and theoretical information on MgSiO_3 and CaSiO_3, and explain discrepancies in previous work". We attain some progress in measurements of silicate melt structure at high pressures. However, as shown in the title of the paper, the research is still "exploratory" and requires further development of experimental techniques, for example, to extend the pressure limit.
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