SONG Mao-shuang1,2, ZHOU Wei1,3, ZHANG Gui-nan1,3, LI Hong-ting1,3
(1. State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;
2. CREST, Japan Science and technology Corporation, Kawaguchi, Saitama 332-0012, Japan;
3. School of Chinese Academy of Sciences, Beijing 100049, China)
Abstract: A detailed infrared absorption study on D2O ice was conducted in P and T ranges of 2–100 GPa and 12–298 K, respectively. The ice Ⅶ-Ⅷ transition was well characterized by the observed spectral changes across the phase boundary, especially the frequency of bending vibration, which was located approximately at 1180 cm-1 in ice Ⅶ and 1100 cm-1 in ice Ⅷ. The frequency of the v2 bending mode shows an anomalous softening below 10 GPa in both ice Ⅶ and ice Ⅷ, indicating a structural relaxation in both phases. The molecular phase Ⅷ was founded to transform into translationally-disordered ice Ⅹ (non-molecular phase) at 75 GPa below 100 K and this phase transition was characterized by the rotational-distortional peak conversion. The appearance of the vD distortional mode was interpreted here to arise from the formation of proton tetrahedron due to proton tunneling along the hydrogen-bonded O-O axis.
Key words: deuterium ice; high-pressure; low-temperature; infrared absorption spectrum; phase transition; hydrogen-bond centering
ACTA MINERALOGICA SINICA Vol. 34, No. 2, 2014, Page 145-152
