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First principles calculation of a high‐pressure hydrous phase, δ‐AlOOH
Author(s) -
Tsuchiya Jun,
Tsuchiya Taku,
Tsuneyuki Shinji,
Yamanaka Takamitsu
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl015417
Subject(s) - bulk modulus , hydrogen , phase (matter) , hydrogen bond , mantle (geology) , moduli , thermodynamics , mineralogy , materials science , geology , chemistry , physics , geochemistry , molecule , organic chemistry , quantum mechanics
Using a first principles method, we have investigated the crystal structure of a high‐pressure phase of AlOOH (δ‐AlOOH). It is an important substance in subducting sedimentary rocks, and could possibly serve as a water reservoir in the Earth's lower mantle. Three types of stable structure were obtained with various hydrogen positions. Two of them have an asymmetric hydrogen bond and the other a symmetric one. The asymmetric hydrogen bond of the low‐pressure phase transforms to the symmetrized one under high pressure. The symmetrized phase has a much larger bulk modulus than the asymmetrized phases. The optimized structures and their respective bulk moduli obtained from our calculation indicate that the subtle change of hydrogen position causes a significant effect on the hydrogen bonding nature and elastic properties of δ‐AlOOH.