X-ray diffraction study of protactinium metal to 53 GPa

Benedict, U.; Spirlet, J.C.; Dufour, C.; Birkel, I.; Holzapfel, W. B.; Peterson, J.R.

doi:10.1016/0304-8853(82)90252-9

Cited by 44 publications

(8 citation statements)

References 9 publications

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“…We are in agreement with the findings from the earlier experimental study by Benedict et al 25 that the bct structure of protactinium is the stable structure up to at least 53 GPa, the highest pressure reached in that work. We determined further that the Pa-I form is stable up to ϳ77 GPa, which accounts for the fact that the Pa-II phase was not observed in the earlier study.…”

Section: A Pa-i Structuresupporting

confidence: 94%

“…1 This was observed in comparing our protactinium values with those previously reported. 25 We believe that our modulus for protactinium metal is a more realistic value. We shall not dwell on the specific aspects for the differences in values reported previously for the modulus or its derivative, but note that nonhydrostatic experimental conditions ͑i.e., the solidification of the transmitting media, especially in the critical, lower pressure segments of the compression data͒ can lead to significant errors.…”

Section: Rietveld Analyses Of Datamentioning

confidence: 91%

“…The agreement in the Rietveld fit ͑Bragg R value for the refinement is 2%͒ provides a high degree of confidence in the structural assignment. Lattice parameters In the earlier study of protactinium up to 53 GPa, 25 the bulk modulus and first derivative were reported as being 157 ͑5͒ GPa and 1.5 ͑0.5͒, respectively. This modulus is significantly larger than found here.…”

Section: Rietveld Analyses Of Datamentioning

confidence: 98%

“…The difference in bulk modulus will be addressed in a subsequent section, but we observed a greater compressibility ͑i.e., a smaller bulk modulus͒ for it than had been reported. 25 The variation and progression with pressure of each of the lattice parameters for the Pa-I phase are shown in Fig. 2.…”

Section: A Pa-i Structurementioning

confidence: 99%

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Pressure-induced changes in protactinium metal: Importance to actinide-metal bonding concepts

Haire

Heathman²,

Idiri³

et al. 2003

Phys. Rev. B

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Protactinium occupies an important position in the actinide series of elements, as it represents the first of four elements ͑Pa-Pu͒ having 5 f -electron character in their bonding at atmospheric pressure. We have determined in experimental studies with synchrotron radiation to 130 GPa, that the tetragonal structure of protactinium ͑space group I4/mmm) converts to an orthorhombic, alpha-uranium structure ͑space group Cmcm͒ at 77͑5͒ GPa, where the atomic volume has been reduced by ϳ30%. This structural change is interpreted as reflecting an increase in 5 f -electron contribution to the bonding in protactinium over that initially present, becoming more similar to that present in alpha-uranium metal at atmospheric pressure. We determined experimentally that this structural transformation occurred at significantly higher pressures and at a smaller atomic volume than predicted by theory. The experimental results reported here represent the highest pressures under which protactinium metal has been studied.

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Section: A Pa-i Structuresupporting

confidence: 94%

Section: Rietveld Analyses Of Datamentioning

confidence: 91%

Section: Rietveld Analyses Of Datamentioning

confidence: 98%

Section: A Pa-i Structurementioning

confidence: 99%

See 2 more Smart Citations

Pressure-induced changes in protactinium metal: Importance to actinide-metal bonding concepts

Haire

Heathman²,

Idiri³

et al. 2003

Phys. Rev. B

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“…The calculated energies for each combination were then fitted with either a cubic function of the volume or a second-order Birch fit, 19 to obtain the zero-pressure volume (V 0 ) and bulk modulus (B 0 ). The fitted results are compared with previous calculations [3][4][5] and experiment [20][21][22][23][24][25][26][27][28][29][30][31] in Tables I and II. We have performed these calculations in both the fcc ͑Pearson cF4͒ and experimentally determined ␣ structures, in order to determine to what extent the cubic close-packed structure can serve as a surrogate for the more complex ͑and much more computationally demanding͒ ␣ structures.…”

Section: Resultsmentioning

confidence: 99%

Theoretical atomic volumes of the light actinides

et al. 2000

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The zero-pressure zero-temperature equilibrium volumes and bulk moduli are calculated for the light actinides Th through Pu using two independent all-electron, full-potential, electronic-structure methods: the full-potential linear augmented-plane-wave method and the linear combinations of Gaussian-type orbitalsfitting function method. The results produced by these two distinctly different electronic-structure techniques are in good agreement with each other, but differ significantly from previously published calculations using the full-potential linear muffin-tin-orbital ͑FP-LMTO͒ method. The theoretically calculated equilibrium volumes are in some cases nearly 10% larger than the previous FP-LMTO calculations, bringing them much closer to the experimentally observed volumes. We also discuss the anomalous upturn in equilibrium volume seen experimentally for ␣-Pu.

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Structural properties of crystalline uranium from linear combination of Gaussian-type orbitals calculations

Boettger

Jones

Albers

1999

Int. J. Quant. Chem.

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Scalar‐relativistic linear combinations of Gaussian‐type orbitals–fitting function (LCGTO–FF) calculations, using the local density approximation (LDA) and generalized gradient approximation (GGA) to density functional theory, were used to determine the atomic volumes, bulk moduli, and relative stabilities of uranium in the fcc, bcc, and α‐U (orthorhombic) phases. The α‐U phase is found to be the most stable, in agreement with experiment. The LDA yields an atomic volume that is about 7% smaller than experiment, while the GGA produces near perfect agreement with experiment. The numerical stability of the LCGTO–FF results is tested by comparison with a similar series of scalar–relativistic calculations using the full‐potential linearized augmented plane‐wave (FLAPW) method. The results obtained with the two methods are in excellent agreement, demonstrating the ability of the LCGTO–FF method to address the properties of a light actinide metal in its low‐symmetry α phase. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 75: 911–915, 1999

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X-ray diffraction study of protactinium metal to 53 GPa

Cited by 44 publications

References 9 publications

Pressure-induced changes in protactinium metal: Importance to actinide-metal bonding concepts

Pressure-induced changes in protactinium metal: Importance to actinide-metal bonding concepts

Theoretical atomic volumes of the light actinides

Structural properties of crystalline uranium from linear combination of Gaussian-type orbitals calculations

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