Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Ikeda, Takashi; Katayama, Yoshinori
Teion Kagaku, 71, p.125 - 129, 2013/03
Although liquid water is one of the most abundant materials on earth and most familiar to all of us, the present understanding of liquid water exhibiting various interesting properties depending on the environment is still far from satisfactory. Hence, it is still one of main subjects in vast research fields including physics, chemistry, and biology. In this contribution, we first describe the structural and dynamical properties of water under high temperatures and pressures revealed by combining advanced first principles molecular dynamics simulations and in situ X-ray diffraction experiments. Then, the future prospects for investigating water under higher pressures and temperatures are summarized.
Fukazawa, Hiroshi
Teion Kagaku, 66, p.159 - 167, 2008/03
Water molecules of liquid water, which have dipole, are easily aligned in the electric field. Whether ice in the Universe exists as proton-ordered ices, is a question that has attracted scientific interest. Some ordered ices have ferroelectricity, and long range electrostatic forces caused by the ferroelectricity might be an important factor for planet formation. Our neutron study suggests that myriad big icy-bodies, which exist as dwarf planets and Kuiper Belt Object, consist of thick ferroelectric-ice surface and several inner layers of proton-ordered ices.
Fukazawa, Hiroshi
Teion Kagaku, 64, p.167 - 172, 2006/03
Water molecules are dipolar, and neutron diffraction studies provide evidences that ices VIII and IX (the proton ordered phases of ices VII and III) exist as stable low-temperature phases at high pressure. However, under an atmospheric pressure, the proton of "normal" ice Ih is disordered even though a very low temperature. A question that has long fascinated researchers is whether there is an existence of ferroelectric proton-ordered ice named ice XI as a stable phase, under an atmospheric pressure. This debate becomes an earnest subject: ice XI exists on Pluto? Time-resolved neutron diffraction studies of ice tell new aspects in this subject.
