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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

SMBH binary candidate PKS J2134−0153: possible multi-band periodic variability and inter-band time lags

ABSTRACT Studying the periodic flux-variation behaviour of blazars is vital for probing supermassive black hole binaries and the kinematics of relativistic jets. In this work, we report the detection of multi-band possible periodic variations of the blazar PKS J2134−0153, including infrared ($1.6(\pm 0.4)\times 10^3$ day) and optical ($1.8(\pm 1)\times 10^3$ day) wavelengths. The periods in the infrared and optical bands are statistically consistent with the period in the radio band ($P_{\mathrm{Radio}} = 1760\pm 33$ days, obtained from our previous work). Moreover, flux variations in different bands are correlated with evident inter-band time delays, and the time lags of infrared and optical emission with respect to radio emission are $(3.3\pm 2.3)\times 10^{2}$ days and $(3.0\pm 2.3)\times 10^{2}$ days, respectively. The cross-correlations indicate a common origin of radio, infrared, and optical emission. The relative positions between emission regions of infrared and optical emission and radio emission are estimated according to the time lags, i.e. $0.37\pm 0.26$ and $0.33\pm 0.26$ pc. The relative distances seem to be quantitatively consistent with the theoretical prediction.

Ren, Guo-Wei (ORCID:0000000214978371)↗
DOE OSTI2022

Precision Determination of the Neutral Weak Form Factor of Ca 48

In this work, we report a precise measurement of the parity-violating asymmetry $A_{\rm PV}$ in the elastic scattering of longitudinally polarized electrons from $^{48}{\rm Ca}$. We measure $A_{\rm PV} =2668\pm 106\ {\rm (stat)}\pm 40\ {\rm (syst)}$ parts per billion, leading to an extraction of the neutral weak form factor $F_{\rm W} (q=0.8733$ fm$^{-1}) = 0.1304 \pm 0.0052 \ {\rm (stat)}\pm 0.0020\ {\rm (syst)}$ and the charge minus the weak form factor $F_{\rm ch} - F_{\rm W} = 0.0277\pm 0.0055$. The resulting neutron skin thickness $R_n-R_p=0.121 \pm 0.026\ {\rm (exp)} \pm 0.024\ {\rm (model)}$~fm is relatively thin yet consistent with many model calculations. The combined CREX and PREX results will have implications for future energy density functional calculations and on the density dependence of the symmetry energy of nuclear matter.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Observation of Same-Sign W W Production from Double Parton Scattering in Proton-Proton Collisions at s = 13 TeV

The first observation of the production of W$^\pm$W$^\pm$ bosons from double parton scattering processes using same-sign electron-muon and dimuon events in proton-proton collisions is reported. The data sample corresponds to an integrated luminosity of 138 fb$^{-1}$ recorded at a center-of-mass energy of 13 TeV using the CMS detector at the CERN LHC. Multivariate discriminants are used to distinguish the signal process from the main backgrounds. A binned maximum likelihood fit is performed to extract the signal cross section. The measured cross section for production of same-sign W bosons decaying leptonically is 80.7 $\pm$ 11.2 (stat) $^{+9.5}_{-8.6}$ (syst) $\pm$ 12.1 (model) fb, whereas the measured fiducial cross section is 6.28 $\pm$ 0.81 (stat) $\pm$ 0.69 (syst) $\pm$ 0.37 (model) fb. The observed significance of the signal is 6.2 standard deviations above the background-only hypothesis.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Picometer sensitivity metrology for EUV absorber phase

With growing interest in EUV attenuated phase-shift masks due to their superior image quality for applications such as dense contact and pillar arrays, it is becoming critical to model, measure, and monitor the intensity and relative phase of multilayer and absorber reflections. We present a solution based on physical modeling of reflectometry data, which can achieve single picometer phase precision and sensitivity to changes in average film thickness below one atomic monolayer. We measure absorber and multilayer reflectivity to determine thin-film parameters with a multidimensional optimization and then acquire a new measurement of either multilayer or absorber to determine perturbations in surface contamination thickness. While it is difficult to assess the accuracy of the first step, the simplicity of the second step allows us to characterize our sensitivity to changes in contamination thickness. Thus, we apply this analysis using an initial set of measurements and repeated measurements after a period of storage. For the multilayer, the total contamination growth was 1068 pm, which occurred almost exclusively during storage (1085 pm) and decreased very slightly during repeated measurements (-17 pm). For the absorber, the behavior was quite different, with a total growth of 126 pm, which occurred much less during storage (28 pm) and primarily during repeated measurements (98 pm). Ultimately, the change in relative phase (absorber minus multilayer) was -0.86 deg for the multilayer and -1.12 deg for the absorber. We estimate the precision of the surface contamination measurement to be 3σ < 6 pm for measuring thickness and 3σ < 0.2 deg for measuring phase.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Effects of Intrusive Confining Units on Groundwater Flow at Pahute Mesa, Nevada National Security Site

Geological, geophysical, hydrogeological, and hydrological evidence indicates that feeder dikes to rhyolitic lava flows may play a role as confining units in the groundwater flow system underlying the Pahute Mesa (PM) area of underground nuclear testing at the Nevada National Security Site (NNSS) (Figure 1). Of geological significance, the PM testing area is largely situated within the Silent Canyon caldera complex (SCCC), which includes both tuffs and lavas that were fed by (and are connected to) intrusive rock units such as feeder dikes prior to and during volcanic eruptions (Orkild et al., 1968; Byers et al., 1976a). Groundwater modeling results presented in this report support extension of “pool-dam” and “breach scenario” concepts presented in Jackson and Fenelon (2018) and Jackson et al. (2021) to low-permeability intrusive confining units (ICUs) such as feeder dikes that are expected to dissect and ring silicic calderas. As laterally extensive, steeply-dipping, and sub-parallel planar structures, ICUs may further compartmentalize groundwater flow in some areas of the volcanic aquifer system at PM. ICUs may explain unusually high horizontal hydraulic gradient southwest of Cheshire. Breaching of an ICU within which the Cheshire test was emplaced may explain changes in water levels before and after the Cheshire test was detonated in the U-20n emplacement hole on 2/14/76 (USDOE, 2015b). This analysis of the effects of ICUs on groundwater flow at PM addresses a need to evaluate uncertainty in the conceptual model or structural aspects of hydrologic source term (HST) or corrective action unit (CAU) models for groundwater flow and contaminant transport (FFACO, 1996, as amended). At Cheshire and possibly other test locations at PM, downgradient extent of radionuclide contamination may be overpredicted by not including the confining effects of ICUs. On the other hand, contaminant extent may be underpredicted by not considering transient flow effects and/or the re-equilibrated flow field caused by breaching of an ICU by an underground nuclear test. Near Cheshire, the effects of ICUs may be most apparent and impactful to the groundwater flow system at PM because of an unusual combination of thickness, extent, and frequency of dikes transecting the saturated CHLFA4 aquifer and feeding into the overlying unsaturated rhyolite lava of Windy Wash. Chapters 2, 3, and 4 present geological, geophysical, hydrogeological, and hydrological evidence for ICUs at PM. Chapters 5 and 6 examine effects of ICUs on groundwater flow including analysis by groundwater modeling.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2026

Influence of Powder Characteristics and Processing Methods on Creep Performance of Powder Metallurgy Hot Isostatic Pressed SS316

The U.S. nuclear energy expansion goals are driving the demand for manufacturing routes that can rapidly produce large, complex, near net shape components. Powder metallurgy hot isostatic pressing (PM HIP) is an advanced manufacturing technique that can be economically scaled-up, while alleviating the supply chain challenges that forging and casting face in terms of cost and lead time constraints. This makes PM-HIP a viable technology to aid and accelerate large-scale part manufacturing for nuclear applications. However, large-scale qualification and deployment of this technology require a thorough understanding of the influence of powder feedstock quality, powder handling history, hot isostatic pressing (HIP) parameters, and subsequent heat treatment on microstructural evolution and elevated temperature mechanical performance. The present work focusses on 316 austenitic stainless steel (SS316) which is most commonly used in high temperature environments for nuclear applications Results from this study show that PM HIPed SS316 meets ASME tensile requirements at room temperature and at elevated temperature. However, creep performance of PM-HIPed SS316 remains inferior to its wrought counterpart, demonstrating that tensile performance alone is not a reliable metric for long duration high temperature integrity. Further, this report delineates powder derived microstructural features that govern creep damage, with key evidences pointing to “microstructural inheritance” from gas atomized powder feedstocks. Commercial SS316 powders of varying chemical compositions and recycling histories were studies, and the results showed large differences in elemental segregation, oxide surface layers and secondary phase distributions. Multi-scale characterization revealed segregation of chromium, molybdenum, manganese and silicon at the boundaries and the precipitation of manganese-, silicon-, and molybdenum-oxides. During HIP consolidation, these surface oxides transform into decorated prior particle boundaries (PPBs) and grain boundary inclusions that persist through conventional post-HIP solution annealing treatment. The retained oxides in post-HIP microstructures were found to influence grain growth, precipitation behavior, and ultimately creep cavitation and fracture. Such post-HIP heat treatments are therefore limited by a complex trade-off between grain growth, and oxide coarsening which aggravate creep damage by acting as nucleation sites for cavities. The objective of this work is to establish an integrated processing–structure–property framework for PM-HIP 316 stainless steel by investigating the influence of powder feedstock characteristics in pre- and post-HIP processing as well as to understand the significance of post-HIP heat treatment on microstructural evolution and creep properties. The results from this report emphasize the significance of powder feedstock integrity in improving creep performance of PM-HIPed SS316, by highlight the effect of rapid solidification, elemental segregation, oxide formation and powder recycling on microstructural defect inheritance following HIP consolidation. Rather than considering HIP processing, solution annealing, and mechanical performance independently, this report treats powder production, HIP consolidation, post-HIP thermal processing, and creep deformation as interconnected stages within a continuous metallurgical process. The resulting framework will provide a scientific basis for developing feedstock engineering strategies capable of improving long-term reliability of PM-HIP stainless steels and accelerating their qualification for advanced nuclear applications.

Ajjarapu, Pavan [Oak Ridge National Laboratory (OR↗
DOE OSTI2020

Air quality impact of the Northern California Camp Fire of November 2018

The Northern California Camp Fire that took place in November 2018 was one of the most damaging environmental events in California history. Here, we analyze ground-based station observations of airborne particulate matter that has a diameter <2.5 µm (PM 2.5 ) across Northern California and conduct numerical simulations of the Camp Fire using the Weather Research and Forecasting model online coupled with chemistry (WRF-Chem). Simulations are evaluated against ground-based observations of PM 2.5 , black carbon, and meteorology, as well as satellite measurements, such as Tropospheric Monitoring Instrument (TROPOMI) aerosol layer height and aerosol index. The Camp Fire led to an increase in Bay Area PM 2.5 to over 50 µg m –3 for nearly 2 weeks, with localized peaks exceeding 300 µg m –3 . Using the Visible Infrared Imaging Radiometer Suite (VIIRS) high-resolution fire detection products, the simulations reproduce the magnitude and evolution of surface PM 2.5 concentrations, especially downwind of the wildfire. The overall spatial patterns of simulated aerosol plumes and their heights are comparable with the latest satellite products from TROPOMI. WRF-Chem sensitivity simulations are carried out to analyze uncertainties that arise from fire emissions, meteorological conditions, feedback of aerosol radiative effects on meteorology, and various physical parameterizations, including the planetary boundary layer model and the plume rise model. Downwind PM 2.5 concentrations are sensitive to both flaming and smoldering emissions over the fire, so the uncertainty in the satellite-derived fire emission products can directly affect the air pollution simulations downwind. Our analysis also shows the importance of land surface and boundary layer parameterization in the fire simulation, which can result in large variations in magnitude and trend of surface PM 2.5 . Inclusion of aerosol radiative feedback moderately improves PM 2.5 simulations, especially over the most polluted days. Results of this study can assist in the development of data assimilation systems as well as air quality forecasting of health exposures and economic impact studies.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Global source apportionment of aerosols into major emission regions and sectors over 1850–2017

Anthropogenic emissions of aerosols and precursor gases have changed significantly in the past few decades around the world. In this study, the Explicit Aerosol Source Tagging (EAST) system is merged into the Energy Exascale Earth System Model version 1 (E3SMv1) to quantify the variations in anthropogenic aerosol concentrations, source contributions, and their subsequent radiative impact in four major emission regions across the globe during 1850–1980, 1980–2010, and 2010–2017. In North America and Europe, changes in anthropogenic PM 2.5 were mainly caused by changes in emissions from local energy and industrial sectors. The local industrial sector caused the largest increase in PM 2.5 in East Asia during 1980–2010 and decrease during 2010–2017. In South Asia, the increase in energy-related emissions dominated the rise in PM 2.5 levels during 1980–2017. During 1850–1980, the increases in emissions from North America contributed to the increase in the European PM 2.5 burden by 1.7 mg m -2 and the sources from the Europe were also responsible for the PM 2.5 burden increase in East Asia and South Asia by about 1.0 mg m -2 . During 1980–2010, East Asia contributed to an increase of 0.4–0.6 mg m -2 in the PM 2.5 burden in North America and Europe, while South Asia contributed about 0.3 mg m -2 . During 2010–2017, the contributions from East Asia to the PM 2.5 burdens in the North America, Europe, and South Asia declined by 0.3–0.6 mg m -2 due to the clean air actions in China, while the contributions from South Asia still increased due to the continuous increase in emissions in South Asia. The historical changes in aerosols had an impact on effective radiative forcing through aerosol–radiation interactions (ERF ari ). During 1980–2010, a decline in North American aerosols resulted in a positive ERF ari change (warming effect) in Europe and a decline in aerosols in Europe caused a warming effect in Russia and northern China. The changes in ERF ari from the increase and decrease in aerosols in China during 1980–2010 and 2010–2017, respectively, are comparable in magnitude. The continuous aerosol increases in South Asia from 1980 to 2017 resulted in negative ERF ari (cooling) changes in South Asia, Southeast Asia, and southern China.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Integration of Nuclear Material Accounting Data and Process Monitoring Data for Improvement on Detection Probability in Safeguarding Electrochemical Processing Facilities (Final Technical Report)

The KAERI advanced spent fuel conditioning process (ACP) process is a critical component of the US- South Korean nuclear cooperation and the following “123 Agreement.” Its development has received considerable attention in both countries. The ACP is an electrochemical processing (pyroprocessing) that recycles over 96% of the used nuclear fuel (UNF). It is also intrinsically proliferation-resistant in theory. In normal operation, the U/TRU product is very hot radiologically. In addition, the Cm provides a high level of spontaneous neutrons, making the product unsuitable for weapon use. However, as pointed in some study, “the need for safeguards to protect against the diversion and misuse of separated plutonium applies essentially equally to all grades of plutonium.” As pointed by many studies, the well-established traditional Nuclear Material Accounting (NMA) approach cannot be directly applied to electrochemical processing because of the lack of an input accountability tank, the non-continuous material flow, and the unsatisfactory level of confidence in sampling methods. Therefore, nuclear safeguards remain a grand challenge in the developing of commercial electrochemical separations facilities, especially around the heart of such facilities, the electrorefiner (ER) systems. In contrast to NMA data, process monitoring (PM) data is normally an indirect measurement of the SNM and is acquired much more frequently. In a broad sense, PM includes monitoring by various types of equipment, e.g. radiation detectors, cameras, voltage, current sensors. Because it is already being collected by the operator, the additional cost to safeguards is low. It has long been believed that PM data can supplement NMA data and help improve safeguards, although the benefits are hard to quantify. The U.S. DOE’s Material Protection, Accounting, and Control Technology (MPACT) campaign has made substantial investments into innovative PM sensor technology and predictive model development for real- or near real-time measurement and prediction of molten salt density and level, salt composition and actinide concentration especially Pu, the cell voltage, and the cell current to supplement traditional NMA. For aqueous-based reprocessing facilities, it is reported that PM, integrated with traditional NMA, have a high detection probability for specific diversions. For electrochemical reprocessing, preliminary studies have shown that PM data can support traditional NMA in various ways by providing a basis to estimate some of the in-processing nuclear material inventories. Despite early success, further studies on fusion of PM data and NMA data are still needed, which is the goal of this proposed work.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

Particulate matter sensor

Microfabricated PM sensors measure concentrations of particulate matter (PM) in air. Some sensors improve the accuracy of measurements by accounting for the effect of ambient conditions (e.g., temperature or humidity) on mass-sensitive elements employed to determine a mass of the PM in a stream of air. Some sensors improve the accuracy of measurements by controlling humidity in the stream of air measured by mass-sensitive elements. Some sensors employ a plurality of mass-sensitive elements to extend the useful life of the PM sensor. Some sensors employ one or more mass-sensitive elements and heating elements to cause deposition and allow measurement of different sizes of PM. Some sensors can measure mass concentration of coarse PM in addition to fine PM in a stream of air. Some sensors control the flow rate of a stream of air measured by mass-sensitive elements. Some sensors include features to mitigate electromagnetic interference or electromagnetic signal loss.

Paprotny, Igor↗
DOE OSTI2021

Daily grass reference evapotranspiration with Meteosat Second Generation shortwave radiation and reference ET products

Here we assess the accuracy of estimating daily grass reference evapotranspiration (PM-ET o ) using daily shortwave radiation (R s ) and reference evapotranspiration (ET REF ) products provided by the Meteosat Second Generation (MSG) geostationary satellite delivered by the Satellite Applications Facility on Land Surface Analysis (LSA-SAF) framework. The accuracy of using reanalysis ERA5 shortwave radiation data (R s ERA5 ) provided by the European Center for Medium-Range Weather Forecasts (ECMWF) is also evaluated. The assessments were performed using observed weather variables at 37 weather stations distributed across continental Portugal, where climate conditions range from semi-arid to humid, and 12 weather stations located in Azores islands, characterized by humid, windy and often cloudy conditions. This study&#x27;s use of data from a variety of climate conditions contributed to a unique and innovative assessment of the usability of LSA-SAF and ERA5 products for ET o estimation. The first assessment focused on comparing LSA-SAF estimates of R s (R s LSA-SAF ) against ground stations (R s ground ). The results showed a good matching between the two R s data sets for continental Portugal but a tendency for R s LSA-SAF to under-estimate R s ground in the cloudy islands of Azores. ET o values computed using R s LSA-SAF data and observed temperature, humidity and wind speed (ET o LSA-SAF ) were then compared with PM-ET o estimates with ground-based data, which were used as benchmark; input data of temperature and humidity needed for PM-ET o were quality checked for surface aridity effects. It was observed that ET o LSA-SAF is strongly correlated with PM-ET o (R 2 > 0.97) for most locations in continental Portugal, with regression coefficient of a linear regression forced to the origin ranging between 0.95 and 1.05, mean root mean square error (RMSE) of 0.13 mm d –1 , and Nash and Sutcliff efficiency of modeling (EF) above 0.95. For most Azores locations, ET o LSA-SAF over-estimated PM-ET o . This is likely a consequence of the high spatio-temporal heterogeneity of weather conditions that occur in these oceanic islands together with the different footprints of satellite (averaged over the pixel) and station observations. Reanalysis ERA5 shortwave radiation data presented similar behavior to the LSA-SAF products, however with slightly lower accuracy. The daily LSA-SAF ET REF product (ET REF LSA-SAF ) was assessed and results have shown a good accuracy of this product, with acceptable RMSE and high EF values, for continental Portugal but a low accuracy for the Azores islands. A simplified bias correction approach was shown to improve both ET o derived from the LSA-SAF products, namely for Azores stations, which seem to be representative of smaller areas. The use of the FAO-PM temperature approach (PMT) was also assessed using the R s LSA-SAF and R s ERA5 data, which showed a superiority of the LSA-SAF product for ET o estimations (ET o PMT LSA-SAF ). No significant differences (p < 0.05) were observed in terms of the median value of the RMSE when adopting ET o PMT and ET REF LSA-SAF . Differently, results showed that using the R s LSA-SAF in the PMT approach (ET o PMT LSA-SAF ) produces significantly better RMSE results than ET o PMT and ET REF LSA-SAF . Overall, the performed assessment allows concluding that the use of R s LSA-SAF, and to a lesser extent the use of the R s ERA5 , highly improves the accuracy of computation of ET o when R s observations are not available, including when only temperature data are accessible. The use of the ET REF LSA-SAF product is a good alternative when observed weather data are not available.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Materials Data on PmHo by Materials Project

HoPm crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Ho is bonded to six equivalent Ho and six equivalent Pm atoms to form HoPm6Ho6 cuboctahedra that share corners with eighteen equivalent HoPm6Ho6 cuboctahedra, edges with six equivalent HoPm6Ho6 cuboctahedra, edges with twelve equivalent PmPm6Ho6 cuboctahedra, faces with eight equivalent HoPm6Ho6 cuboctahedra, and faces with twelve equivalent PmPm6Ho6 cuboctahedra. All Ho–Ho bond lengths are 3.64 Å. All Ho–Pm bond lengths are 3.57 Å. Pm is bonded to six equivalent Ho and six equivalent Pm atoms to form PmPm6Ho6 cuboctahedra that share corners with eighteen equivalent PmPm6Ho6 cuboctahedra, edges with six equivalent PmPm6Ho6 cuboctahedra, edges with twelve equivalent HoPm6Ho6 cuboctahedra, faces with eight equivalent PmPm6Ho6 cuboctahedra, and faces with twelve equivalent HoPm6Ho6 cuboctahedra. All Pm–Pm bond lengths are 3.64 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Sc by Materials Project

Pm3Sc is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Pm is bonded to eight equivalent Pm and four equivalent Sc atoms to form distorted PmPm8Sc4 cuboctahedra that share corners with four equivalent ScPm12 cuboctahedra, corners with fourteen equivalent PmPm8Sc4 cuboctahedra, edges with six equivalent ScPm12 cuboctahedra, edges with twelve equivalent PmPm8Sc4 cuboctahedra, faces with four equivalent ScPm12 cuboctahedra, and faces with sixteen equivalent PmPm8Sc4 cuboctahedra. There are a spread of Pm–Pm bond distances ranging from 3.54–3.67 Å. There are two shorter (3.52 Å) and two longer (3.61 Å) Pm–Sc bond lengths. Sc is bonded to twelve equivalent Pm atoms to form ScPm12 cuboctahedra that share corners with six equivalent ScPm12 cuboctahedra, corners with twelve equivalent PmPm8Sc4 cuboctahedra, edges with eighteen equivalent PmPm8Sc4 cuboctahedra, faces with eight equivalent ScPm12 cuboctahedra, and faces with twelve equivalent PmPm8Sc4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LaPm3 by Materials Project

Pm3La is Magnesium-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Pm is bonded to eight equivalent Pm and four equivalent La atoms to form PmLa4Pm8 cuboctahedra that share corners with four equivalent LaPm12 cuboctahedra, corners with fourteen equivalent PmLa4Pm8 cuboctahedra, edges with six equivalent LaPm12 cuboctahedra, edges with twelve equivalent PmLa4Pm8 cuboctahedra, faces with four equivalent LaPm12 cuboctahedra, and faces with sixteen equivalent PmLa4Pm8 cuboctahedra. There are a spread of Pm–Pm bond distances ranging from 3.67–3.73 Å. There are two shorter (3.68 Å) and two longer (3.71 Å) Pm–La bond lengths. La is bonded to twelve equivalent Pm atoms to form LaPm12 cuboctahedra that share corners with six equivalent LaPm12 cuboctahedra, corners with twelve equivalent PmLa4Pm8 cuboctahedra, edges with eighteen equivalent PmLa4Pm8 cuboctahedra, faces with eight equivalent LaPm12 cuboctahedra, and faces with twelve equivalent PmLa4Pm8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Er by Materials Project

ErPm3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Er is bonded to twelve equivalent Pm atoms to form ErPm12 cuboctahedra that share corners with six equivalent ErPm12 cuboctahedra, corners with twelve equivalent PmPm8Er4 cuboctahedra, edges with eighteen equivalent PmPm8Er4 cuboctahedra, faces with eight equivalent ErPm12 cuboctahedra, and faces with twelve equivalent PmPm8Er4 cuboctahedra. There are six shorter (3.60 Å) and six longer (3.66 Å) Er–Pm bond lengths. Pm is bonded to four equivalent Er and eight equivalent Pm atoms to form PmPm8Er4 cuboctahedra that share corners with four equivalent ErPm12 cuboctahedra, corners with fourteen equivalent PmPm8Er4 cuboctahedra, edges with six equivalent ErPm12 cuboctahedra, edges with twelve equivalent PmPm8Er4 cuboctahedra, faces with four equivalent ErPm12 cuboctahedra, and faces with sixteen equivalent PmPm8Er4 cuboctahedra. There are a spread of Pm–Pm bond distances ranging from 3.61–3.67 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YbPm3 by Materials Project

YbPm3 is Magnesium-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Yb is bonded to twelve equivalent Pm atoms to form YbPm12 cuboctahedra that share corners with six equivalent YbPm12 cuboctahedra, corners with twelve equivalent PmYb4Pm8 cuboctahedra, edges with eighteen equivalent PmYb4Pm8 cuboctahedra, faces with eight equivalent YbPm12 cuboctahedra, and faces with twelve equivalent PmYb4Pm8 cuboctahedra. There are six shorter (3.68 Å) and six longer (3.70 Å) Yb–Pm bond lengths. Pm is bonded to four equivalent Yb and eight equivalent Pm atoms to form PmYb4Pm8 cuboctahedra that share corners with four equivalent YbPm12 cuboctahedra, corners with fourteen equivalent PmYb4Pm8 cuboctahedra, edges with six equivalent YbPm12 cuboctahedra, edges with twelve equivalent PmYb4Pm8 cuboctahedra, faces with four equivalent YbPm12 cuboctahedra, and faces with sixteen equivalent PmYb4Pm8 cuboctahedra. There are a spread of Pm–Pm bond distances ranging from 3.64–3.75 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Pr by Materials Project

Pm3Pr is Magnesium-derived structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Pm is bonded to eight equivalent Pm and four equivalent Pr atoms to form PmPm8Pr4 cuboctahedra that share corners with four equivalent PrPm12 cuboctahedra, corners with fourteen equivalent PmPm8Pr4 cuboctahedra, edges with six equivalent PrPm12 cuboctahedra, edges with twelve equivalent PmPm8Pr4 cuboctahedra, faces with four equivalent PrPm12 cuboctahedra, and faces with sixteen equivalent PmPm8Pr4 cuboctahedra. There are a spread of Pm–Pm bond distances ranging from 3.67–3.69 Å. There are two shorter (3.67 Å) and two longer (3.69 Å) Pm–Pr bond lengths. Pr is bonded to twelve equivalent Pm atoms to form PrPm12 cuboctahedra that share corners with six equivalent PrPm12 cuboctahedra, corners with twelve equivalent PmPm8Pr4 cuboctahedra, edges with eighteen equivalent PmPm8Pr4 cuboctahedra, faces with eight equivalent PrPm12 cuboctahedra, and faces with twelve equivalent PmPm8Pr4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PmNd by Materials Project

PmNd is Magnesium-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. Pm is bonded to six equivalent Pm and six equivalent Nd atoms to form PmPm6Nd6 cuboctahedra that share corners with eighteen equivalent PmPm6Nd6 cuboctahedra, edges with six equivalent PmPm6Nd6 cuboctahedra, edges with twelve equivalent NdPm6Nd6 cuboctahedra, faces with eight equivalent PmPm6Nd6 cuboctahedra, and faces with twelve equivalent NdPm6Nd6 cuboctahedra. All Pm–Pm bond lengths are 3.67 Å. All Pm–Nd bond lengths are 3.69 Å. Nd is bonded to six equivalent Pm and six equivalent Nd atoms to form NdPm6Nd6 cuboctahedra that share corners with eighteen equivalent NdPm6Nd6 cuboctahedra, edges with six equivalent NdPm6Nd6 cuboctahedra, edges with twelve equivalent PmPm6Nd6 cuboctahedra, faces with eight equivalent NdPm6Nd6 cuboctahedra, and faces with twelve equivalent PmPm6Nd6 cuboctahedra. All Nd–Nd bond lengths are 3.67 Å.

36 MATERIALS SCIENCE↗