日時 ： ２００９年５月２２日（金）※16：30～
場所 ： 愛媛大学総合研究棟Ⅰ 4F 共通会議室（理学部構内）
要 旨
The essential problems of high pressure neutron experiments are sample volume, i.e., although (weak) 'neutron' requires a large amount of sample volume, 'high pressure' requires a small sample. As a matter of course, ISIS and ILL, the world strongest neutron sources in UK and France lead high pressure neutron science to date. Particularly, the developments of Paris-Edinburgh cell would be the most crucial technical progress. They now permit in situ high pressure and high/low temperature neutron scattering studies for both crystals and amorphous materials. I had joined to the neutron experiments in ISIS and ILL of the group of the Univ. of Edinburgh from Jun/2006 to Mar/2009. In the experiences, the results of the powder diffraction study for d-AlOOH on the D20 in ILL, and the single crystal diffraction studies for squaric acid [H2C4O4] on the SXD in ISIS and D9 in ILL will be presented in this talk. These materials have the relatively strong hydrogen-bonds even at ambient pressure. It has long been discussed whichever such a strong hydrogen-bond has a quantum tunneling state under pressure or not. Although single crystal neutron diffraction under pressure gives us the most precise information for the time and space averaged distribution of the hydrogen, the method had been applied until a few GPa before we manage to measure the data for squaric acid at 10GPa using the Paris-Edinburgh cell. The technical progresses for the single crystal neutron diffraction under pressure up to 10 GPa and some methods for corrections for structural analysis using single crystal data will also be presented.
問い合わせ先：土屋 卓久 TEL （089）927-8198
E-mail takut@sci.ehime-u.ac.jp
