Date: 16:00 – 18:00, Friday, December, 22, 2023
発表者：小林大輝
Author: Hiroki Kobayashi
Title: Hidden experimental parameters that affect the ice VI-XV hydrogen-ordering phase transition
Abstract: Not disclosed
発表者： 高野将大
Speaker: Masahiro Takano
Title: “Hydrogenation” of “FeS” at high-pressure and high-temperature conditions
The hydrogenation of iron sulfide (FeS) under high-pressure and high-temperature conditions has attracted attention because hydrogen and sulfur are promising candidates for the light elements in the cores of the Earth and other terrestrial planets. In the previous studies reporting the hydrogenation of FeS, the chemical compositions of starting materials were not fully clarified. This study reports in-situ neutron and X-ray diffraction measurements on Fe-S-H system using a stochiometric FeS (troilite) as a starting material. The site occupancies of hydrogen atoms in FeS (troilite) were estimated by Rietveld refinement of neutron diffraction patterns collected at about 5 GPa: 0.014(2) at 700 K and 0.024(2) at 1000 K. The hydrogen occupancy at 900 K and 18.2 GPa was estimated to be 0.067(6) from the unit-cell volume determined by X-ray diffraction using the volume expansion induced by hydrogenation calculated from the first-principles calculation. These occupancies were significantly small compared to those of the previous studies, indicating that the stoichiometry of the starting material can have a significant effect on the hydrogenation of FeS.