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The distinguish method of ferroelectric ice is established by the infrared absorption measurement
-Neutron diffraction study boosts understanding of planet formation-

Oct. 20 , 2009

A joint research group has established the distinguish method of ferroelectric ice by the infrared absorption measurement. The infrared absorption spectra of ferroelectric ice, named ice XI, is first obtained using this technique. A broad peak observed at around 850 cm-1 (11.7 µm) was derived from libration of water molecules. The peak width was notably narrower at temperatures less than 140 K. These results are consistent with ordering of hydrogen atoms. The existence of hydrogen-ordered ice in space is the subject of continuing astronomical debate. The ontained results demonstrate that ordered ice in space is detectable using infrared telescopes and planetary exploration. The research group consists of Dr. Hiroshi Fukazawa at Neutron Materials Research Center, Japan Atomic Energy Agency (JAEA) and Prof. Hiroyuki Kagi and Mr. Masashi Arakawa at Graduate School of Science, University of Tokyo.

Based on neutron diffraction studies at a research reactor facility at Oak Ridge, Dr. Fukazawa (Fukazawa et al., Astrophysical Journal 2006) proposed a hypothesis: ferroelectric ice XI exists in cold space environments (e.g., Pluto, the Kuiper Belt objects, and interstellar molecular clouds). However, it was not clear how to prove this hypothesis.

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