TY - JOUR
T1 - Polymorphs of alumina predicted by first principles
T2 - Putting pressure on the ruby pressure scale
AU - Thomson, Kendall T.
AU - Wentzcovitch, Renata M.
AU - Bukowinski, Mark S T
PY - 1996/12/13
Y1 - 1996/12/13
N2 - Fully optimized quantum mechanical calculations indicate that Al2O3 transforms from the corundum structure to the as yet unobserved Rh2O3 (II) structure at about 78 gigapascals, and it further transforms to Pbnm- perovskite structure at 223 gigapascals. The predicted x-ray spectrum of the Rh2O3 (II) structure is similar to that of the corundum structure, suggesting that the Rh2O3 (II) structure could go undetected in high- pressure x-ray measurements. It is therefore possible that the ruby (Cr3+- doped corundum) fluorescence pressure scale is sensitive to the thermal history of the ruby chips in a given experiment.
AB - Fully optimized quantum mechanical calculations indicate that Al2O3 transforms from the corundum structure to the as yet unobserved Rh2O3 (II) structure at about 78 gigapascals, and it further transforms to Pbnm- perovskite structure at 223 gigapascals. The predicted x-ray spectrum of the Rh2O3 (II) structure is similar to that of the corundum structure, suggesting that the Rh2O3 (II) structure could go undetected in high- pressure x-ray measurements. It is therefore possible that the ruby (Cr3+- doped corundum) fluorescence pressure scale is sensitive to the thermal history of the ruby chips in a given experiment.
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U2 - 10.1126/science.274.5294.1880
DO - 10.1126/science.274.5294.1880
M3 - Article
AN - SCOPUS:0030462968
SN - 0036-8075
VL - 274
SP - 1880
EP - 1882
JO - Science
JF - Science
IS - 5294
ER -