Resonant photoemission in<i>f</i>-electron systems: Pu and Gd

Tobin, J. G.; Chung, B W; Schulze, R.; Terry, Jeff; Farr, J. D.; Shuh, David K.; Heinzelman, K.; Rotenberg, Eli; Waddill, G. D.; Laan, G. van der

doi:10.1103/physrevb.68.155109

Cited by 75 publications

(61 citation statements)

References 42 publications

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“…Once the non-metallic phase is realized, a large increase in resonance is observed due to extra atomic decay channels. However, looking at the originally published resonant photoemission of Tobin et al (2003), where data for α-Pu is shown (this spectra is omitted in Chung et al, 2006a), there is practically no difference between α-and δ-Pu. Assuming the argument of Dowben (2000), how could new and old δ-Pu show a large difference in resonant photoemission while α-and δ-Pu are practically the same?…”

Section: Effects Of Agingmentioning

confidence: 99%

Nature of the5fstates in actinide metals

2009

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Actinide elements produce a plethora of interesting physical behaviors due to the 5f states. This review compiles and analyzes progress in understanding of the electronic and magnetic structure of the 5f states in actinide metals. Particular interest is given to electron energy-loss spectroscopy and many-electron atomic spectral calculations, since there is now an appreciable library of core d → valence f transitions for Th, U, Np, Pu, Am, and Cm. These results are interwoven and discussed against published experimental data, such as x-ray photoemission and absorption spectroscopy, transport measurements, and electron, x-ray, and neutron diffraction, as well as theoretical results, such as density-functional theory and dynamical mean-field theory.

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Section: Effects Of Agingmentioning

confidence: 99%

Nature of the5fstates in actinide metals

2009

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“…[1][2][3][4][5] Spectroscopic techniques with fluorescence-based detection are particularly useful and have immediate utility for actinide investigations since they are sensitive to small amounts of material, and can be bulk sensitive, thereby avoiding complications of clean surface preparation and the safety considerations that accompany. A most recent complementary development along these lines has been the use of the scanning transmission x-ray microscopy (STXM) spectromicroscopy to investigate small particles of actinide materials.…”

Section: Introductionmentioning

confidence: 99%

Soft X-ray scanning transmission X-ray microscopy (STXM) of actinide particles

et al. 2005

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A descriptive account is given of our most recent actinide research on the actinide dioxides with the Advanced Light Source Molecular Environmental Science (ALS-MES) Beamline 11.0.2 soft x-ray scanning transmission x-ray microscope (STXM) at the Lawrence Berkeley National Laboratory (LBNL). The ALS-MES STXM permits near-edge x-ray absorption fine structure (NEXAFS) and imaging with 30 nm spatial resolution. The first STXM spectromicroscopy NEXAFS spectra at the actinide 4d 5/2 edges of the imaged transuranic particles, NpO 2 and PuO 2, have been obtained. Radiation damage induced by the STXM was observed in the investigation of a mixed oxidation state particle [Np(V,VI)] and was minimized during collection of the actual spectra at the 4d 5/2 edge of the Np(V,VI) solid. A plutonium elemental map was obtained from an irregular PuO 2 particle with the dimensions of 650 nm x 650 nm. Pu 4d 5/2 NEXAFS spectra were collected at several different locations from the PuO 2 particle and were identical. A representative oxygen K-edge spectrum from UO 2 was collected and resembles the oxygen Kedge from the bulk material. The unique and current performance of the ALS-MES STXM at extremely low energies (~100 eV) that may permit the successful measurement of the actinide 5d edge is documented. Finally, the potential of STXM as a tool for actinide investigations is briefly discussed.

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“…An XAS spectrum from -Pu is also presented [27,28]. The spin-orbit split 4d 3/2 and 4d 5/2 manifolds are clearly resolved for each metal as a pair of white lines.…”

Section: Resultsmentioning

confidence: 99%

“…The XAS spectra were collected at the Advanced Light Source in total-electron-yield mode, using a 30 mg sample of purified -Pu (details are provided elsewhere [27]). …”

Section: Monday March 21 2005mentioning

confidence: 99%

Probing the population of the spin–orbit split levels in the actinide 5f states

et al. 2006

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Spin-orbit interaction in the 5f states is believed to strongly influence exotic behaviors observed in actinides metals and compounds. Understanding these interactions and how they relate to the actinide series is of considerable importance. To address this issue, the branching ratio of the white-line peaks of the N 4,5 edges for the light actinide metals, -Th, -U, and -Pu were recorded using electron energy-loss spectroscopy (EELS) in a transmission electron microscope (TEM) and synchrotron-radiation-based x-ray absorption spectroscopy (XAS). Using the spin-orbit sum rule and the branching ratios from both experimental spectra and many-electron atomic spectral calculations, accurate values of the spin-orbit interaction, and thus the relative occupation of the j = 5/2 and 7/2 levels, are determined for the actinide 5f states. Results show that the spin-orbit sum rule works very well with both EELS and XAS spectra, needing little or no correction. This is important, since the high spatial resolution of a TEM can be used to overcome the problems of single crystal growth often encountered with actinide metals, allowing acquisition of EELS spectra, and subsequent spin-orbit analysis, from nm-sized regions.The relative occupation numbers obtained by our method have been compared with recent theoretical results and show a good agreement in their trend.

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Resonant photoemission inf-electron systems: Pu and Gd

Cited by 75 publications

References 42 publications

Nature of the5fstates in actinide metals

Nature of the5fstates in actinide metals

Soft X-ray scanning transmission X-ray microscopy (STXM) of actinide particles

Probing the population of the spin–orbit split levels in the actinide 5f states

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