A structural study of promethium metal under pressure |
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Authors: | R. G. Haire S. Heathman U. Benedict |
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Affiliation: | 1. Chemistry Division , Transuranium Research Laboratory, Oak Ridge National Laboratory, RO. Box 2008 , Oak Ridge, TN, 37831-6375, USA;2. Commission of the European Communities Joint Research Centre , Institute for Transuranium Elements, Postfach 2340 , D-7500, Karlsruhe, FRG |
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Abstract: | Abstract The structural behaviour of Pm metal has been investigated up to 60 GPa of pressure using a Diamond Anvil Cell (DAC) and the energy dispersive X-ray diffraction technique. The room temperature/pressure structural form of Pm is dhcp and it transforms to a fcc phase by 10 GPa. This cubic phase of the metal converts by 18 GPa to a third phase, which has frequently been referred to as representing a distorted fcc structure. This latter form of Pm was retained up to 60 GPa, the maximum pressure studied, but subtle changes in the X-ray spectra between 50 and 60 GPa hinted that an additional structural change could be forthcoming at higher pressures. From the experimental data a bulk modulus (B0) of 38 GPa and a B0′ constant of 1.5 were calculated using the Birch equation. This modulus for Pm is in accord with the moduli reported for the neighboring lanthanide metals. |
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