Showing papers by "Peter M. Bell published in 1988"
TL;DR: In this article, the authors measured the room temperature static compression of CaO in a diamond anvil cell to 1.35 Mbar and showed that the B2 phase is slightly more compressible at room temperature than deduced from shock wave experiments.
Abstract: The room temperature static compression of CaO has been measured in a diamond anvil cell to 1.35 Mbar. The compression of the Bl phase and the volume change at the Bl to B2 transition agree with previous diamond cell results. The B2 phase has been observed down to 527 kbar and seems slightly more compressible at room temperature than deduced from shock wave experiments. Eulerian as well as semiempirical equations of state account well for the data and yield similar bulk moduli for both phases as a function of pressure. Equation-of-state parameters are Ko = 1.11 ± 0.01 and 1.3 ± 0.2 Mbar and Ko′ = 4.2 ± 0.2 and 3.5 ± 0.5 for the Bl and B2 phases, respectively, and Vo = 14.8 ± 0.2 cm3/mol for the B2 phase. For a pressure of 550 kbar, at which no data extrapolations are required, one finds K = 3.04 and 2.96 Mbar with K′ values of about 3.0 and 2.5 for the Bl and B2 phases, respectively. Recent theoretical structure calculations predict room temperature compressions in fair agreement with the static results.
122 citations
08 Aug 1988
TL;DR: In the last five years, high-pressure experimental data on planetary materials are critical in developing planetary models and in addressing otherwise insoluble problems of the internal structure of the major planets.
Abstract: High-pressure experimental data on planetary materials are critical in developing planetary models and in addressing otherwise insoluble problems of the internal structure of the major planets. Progress in the last five years has been particularly marked. Maximum static pressure of 550 GPa was achieved. For the first time, X-ray diffraction of solidified gases (Ne, Xe) and ices (H2O) were obtained at pressures above one megabar, single-crystal diffraction of ultralight elements (H2, He) were detected up to 25 GPa, pressures over 200 GPa at 77 K were reached in solid hydrogen, including the discovery of a phase transformation in the molecular solid. Advances in instrumentation and new measurements performed during 1983 to 1988 are summarized.