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At least 1,639 records · Page 91
All sourcesNASA NTRSDOE OSTI
NASA NTRS2011

Toward a Framework for Systematic Error Modeling of NASA Spaceborne Radar with NOAA/NSSL Ground Radar-Based National Mosaic QPE

Characterization of the error associated to satellite rainfall estimates is a necessary component of deterministic and probabilistic frameworks involving space-born passive and active microwave measurement") for applications ranging from water budget studies to forecasting natural hazards related to extreme rainfall events. We focus here on the error structure of NASA's Tropical Rainfall Measurement Mission (TRMM) Precipitation Radar (PR) quantitative precipitation estimation (QPE) at ground. The problem is addressed by comparison of PR QPEs with reference values derived from ground-based measurements using NOAA/NSSL ground radar-based National Mosaic and QPE system (NMQ/Q2). A preliminary investigation of this subject has been carried out at the PR estimation scale (instantaneous and 5 km) using a three-month data sample in the southern part of US. The primary contribution of this study is the presentation of the detailed steps required to derive trustworthy reference rainfall dataset from Q2 at the PR pixel resolution. It relics on a bias correction and a radar quality index, both of which provide a basis to filter out the less trustworthy Q2 values. Several aspects of PR errors arc revealed and quantified including sensitivity to the processing steps with the reference rainfall, comparisons of rainfall detectability and rainfall rate distributions, spatial representativeness of error, and separation of systematic biases and random errors. The methodology and framework developed herein applies more generally to rainfall rate estimates from other sensors onboard low-earth orbiting satellites such as microwave imagers and dual-wavelength radars such as with the Global Precipitation Measurement (GPM) mission.

Kirstettier, Pierre-Emmanual↗
NASA NTRS2015

Tropical Cyclone Diurnal Cycle as Observed by TRMM

Using infrared satellite data, previous work has shown a consistent diurnal cycle in the pattern of cold cloud tops around mature tropical cyclones. In particular, an increase in the coverage by cold cloud tops often occurs in the inner core of the storm around the time of sunset and subsequently propagates outward to several hundred kilometers over the course of the following day. This consistent cycle may have important implications for structure and intensity changes of tropical cyclones and the forecasting of such changes. Because infrared satellite measurements are primarily sensitive to cloud top, the goal of this study is to use passive and active microwave measurements from the Tropical Rainfall Measurement Mission (TRMM) Microwave Imager (TMI) and Precipitation Radar (PR), respectively, to examine and better understand the tropical cyclone diurnal cycle throughout a larger depth of the storm's clouds. The National Hurricane Center's best track dataset was used to extract all PR and TMI pixels within 1000 km of each tropical cyclone that occurred in the Atlantic basin between 1998-2011. Then the data was composited according to radius (100-km bins from 0-1000 km) and local standard time (LST; 3-hr bins). Specifically, PR composites involved finding the percentage of pixels with reflectivity greater than or equal to 20 dBZ at various heights (i.e., 2-14 km in increments of 2 km) as a function of radius and time. The 37- and 85- GHz TMI channels are especially sensitive to scattering by precipitation-sized ice in the mid to upper portions of clouds. Hence, the percentage of 37- and 85-GHz polarization corrected temperatures less than various thresholds were calculated using data from all storms as a function of radius and time. For 37 GHz, thresholds of 260 K, 265 K, 270 K, and 275 K were used, and for 85 GHz, thresholds of 200-270 K in increments of 10 K were utilized. Note that convection forced by the interactions of a tropical cyclone with land (e.g., due to frictional convergence) may disrupt the natural convective cycle of a cyclone. Hence, only data pertaining to storms whose centers were greater than 300 km from land were included in the composites. Early results suggest the presence of a diurnal cycle in the PR composites of all Atlantic basin tropical cyclones from a height of 2-12 km from approximately 0-400 km radius, but the cycle is most apparent above 6 km. At a height of 8 km, there is a peak (minimum) in the percentage of PR pixels greater than or equal to 20 dBZ near 0 (21) LST in the inner core with some indication that this signal propagates outward with time. In contrast, the 37- and 85-GHz composites show little indication of a diurnal cycle at any radii, regardless of the threshold used. Ongoing work with this project will involve sub-setting the composites according to storm intensity to see if the diurnal cycle varies with storm strength. Moderate to strong vertical wind shear often leads to asymmetries in tropical cyclone convection and may disrupt the cyclone's natural diurnal cycle. Therefore, wind shear thresholds will be applied to the composites to determine if the diurnal cycle becomes more apparent in a low shear environment. Finally, other work to be completed will involve developing composites for other tropical cyclone basins, including the East Pacific, Northwest Pacific, South Pacific, and Indian Ocean.

tropical cyclones↗
NASA NTRS2023

Desert Research and Technology Studies (D-RATS) 2022 Test Report

The primary purpose of the 2022 Desert Research and Technology Studies (D-RATS 22) analog mission field test was to provide data and recommendations regarding how pressurized rover (PR) design, cabin configuration, driving modes, timeline constraints, and mission operations can be acceptably implemented to support future Artemis missions that include a PR. The goal of these evaluations was to provide first order feedback and data on design concepts currently being traded as options for future pressurized rover flight prototypes. The Japan Aerospace Exploration Agency (JAXA) may provide a PR for future Artemis missions. One of the primary objectives of D-RATS 2022 was to share with the JAXA PR team the processes and protocols by which NASA has learned to successfully evaluate rover concepts through integrated HITL evaluations over the past 20+ years, so that JAXA could apply any applicable lessons learned to their PR design, development, testing, and evaluation.

analog↗
DOE OSTI2025

User Acceptance of Shared Autonomous Vehicles

A dissertation is proposed to explore user acceptance of shared autonomous vehicles (SAVs). SAVs are facing limited user acceptance. To systematically tackle the user acceptance barriers of SAVs, the main problem can be disintegrated into two sub-problems of user acceptance of autonomous vehicles (AVs) and ridesharing. The comfort of the ride experience in AVs is a determinant of user acceptance. Understanding the influential factors and developing methodologies to quantify human comfort in AVs are essential to facilitating future research to improve human comfort in AVs. The current pooled rideshare (PR) service closely resembles the anticipated future of SAVs. Understanding why users prefer or refuse to use PR at the current stage prepares SAVs for broader acceptance in the future. Until now, a series of peer-reviewed publications have been published to achieve the technical goals. Two simulator-based user studies were conducted to instrument the research on human comfort in AVs. Statistical analysis was performed to identify the crucial vehicular behavioral factors of human comfort in AVs. The influential factors of human comfort in AVs and methodologies to quantify and detect human comfort in AVs were investigated. Two survey-based studies were deployed to facilitate the investigation of user acceptance of rideshare services. The influential factors of users' willingness to consider PR were explored and identified, and the choice behaviors in ridesharing services were comprehensively modeled and analyzed. The proposed research answers a series of fundamental questions regarding the user acceptance of SAVs. For the branch of user acceptance of AVs, the research generated guidelines for improving passenger comfort in AVs by identifying a series of autonomous driving factors of passenger comfort. The research also provides fundamental tools to estimate human comfort levels for future research and in-AV applications. For the branch of user acceptance of PR, the research provided user acceptance-aware vehicle, service, and policy design insights that can promote the usage of PR.

Su, Haotian↗
DOE OSTI2020

Materials Data on Pr2Se2O by Materials Project

Pr2Se2O crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 1-coordinate geometry to six Se2- and one O2- atom. There are a spread of Pr–Se bond distances ranging from 2.96–3.15 Å. The Pr–O bond length is 2.40 Å. In the second Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to three Se2- and three equivalent O2- atoms. There are a spread of Pr–Se bond distances ranging from 3.02–3.17 Å. There are one shorter (2.41 Å) and two longer (2.44 Å) Pr–O bond lengths. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 5-coordinate geometry to five Pr3+ atoms. In the second Se2- site, Se2- is bonded in a 4-coordinate geometry to four Pr3+ atoms. O2- is bonded to four Pr3+ atoms to form a mixture of corner and edge-sharing OPr4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrZn5 by Materials Project

PrZn5 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Pr is bonded in a 6-coordinate geometry to eighteen Zn atoms. There are six shorter (3.13 Å) and twelve longer (3.45 Å) Pr–Zn bond lengths. There are two inequivalent Zn sites. In the first Zn site, Zn is bonded to four equivalent Pr and eight Zn atoms to form a mixture of corner, edge, and face-sharing ZnPr4Zn8 cuboctahedra. There are four shorter (2.65 Å) and four longer (2.71 Å) Zn–Zn bond lengths. In the second Zn site, Zn is bonded in a 12-coordinate geometry to three equivalent Pr and six equivalent Zn atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr4Si2Se3O7 by Materials Project

Pr4Si2Se3O7 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. there are two inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 9-coordinate geometry to three Se2- and six O2- atoms. There are one shorter (2.99 Å) and two longer (3.03 Å) Pr–Se bond lengths. There are a spread of Pr–O bond distances ranging from 2.55–2.68 Å. In the second Pr3+ site, Pr3+ is bonded in a 6-coordinate geometry to three Se2- and three O2- atoms. There are one shorter (3.00 Å) and two longer (3.02 Å) Pr–Se bond lengths. There are one shorter (2.42 Å) and two longer (2.53 Å) Pr–O bond lengths. Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.65–1.67 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted square co-planar geometry to four equivalent Pr3+ atoms. In the second Se2- site, Se2- is bonded in a 6-coordinate geometry to four equivalent Pr3+ and two equivalent O2- atoms. Both Se–O bond lengths are 3.45 Å. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to four Pr3+ atoms. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Si4+ and one Se2- atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Pr3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr2Ti2O7 by Materials Project

Pr2Ti2O7 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are four inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.35–2.48 Å. In the second Pr3+ site, Pr3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.42–2.69 Å. In the third Pr3+ site, Pr3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pr–O bond distances ranging from 2.37–2.89 Å. In the fourth Pr3+ site, Pr3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.38–2.62 Å. There are four inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 22–45°. There are a spread of Ti–O bond distances ranging from 1.78–2.36 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 22–41°. There are a spread of Ti–O bond distances ranging from 1.86–2.29 Å. In the third Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 19–45°. There are a spread of Ti–O bond distances ranging from 1.82–2.37 Å. In the fourth Ti4+ site, Ti4+ is bonded to six O2- atoms to form distorted corner-sharing TiO6 octahedra. The corner-sharing octahedra tilt angles range from 19–41°. There are a spread of Ti–O bond distances ranging from 1.83–2.33 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to two Pr3+ and two Ti4+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two Pr3+ and two Ti4+ atoms. In the third O2- site, O2- is bonded to three Pr3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing OPr3Ti tetrahedra. In the fourth O2- site, O2- is bonded to three Pr3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing OPr3Ti tetrahedra. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two Pr3+ and one Ti4+ atom. In the sixth O2- site, O2- is bonded to three Pr3+ and one Ti4+ atom to form a mixture of distorted edge and corner-sharing OPr3Ti tetrahedra. In the seventh O2- site, O2- is bonded to two Pr3+ and two Ti4+ atoms to form a mixture of distorted edge and corner-sharing OPr2Ti2 tetrahedra. In the eighth O2- site, O2- is bonded to two Pr3+ and two Ti4+ atoms to form a mixture of distorted edge and corner-sharing OPr2Ti2 tetrahedra. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Pr3+ and two Ti4+ atoms. In the tenth O2- site, O2- is bonded to two Pr3+ and two Ti4+ atoms to form a mixture of distorted edge and corner-sharing OPr2Ti2 tetrahedra. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+ and two equivalent Ti4+ atoms. In the twelfth O2- site, O2- is bonded in a 5-coordinate geometry to three Pr3+ and two equivalent Ti4+ atoms. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Pr3+ and two Ti4+ atoms. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to two Pr3+ and two Ti4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr4Ga2O9 by Materials Project

Pr4Ga2O9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are four inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.40–2.77 Å. In the second Pr3+ site, Pr3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Pr–O bond distances ranging from 2.36–3.01 Å. In the third Pr3+ site, Pr3+ is bonded to six O2- atoms to form PrO6 octahedra that share corners with three equivalent GaO4 tetrahedra, corners with two equivalent GaO4 trigonal pyramids, and edges with two equivalent PrO7 hexagonal pyramids. There are a spread of Pr–O bond distances ranging from 2.34–2.49 Å. In the fourth Pr3+ site, Pr3+ is bonded to seven O2- atoms to form distorted PrO7 hexagonal pyramids that share a cornercorner with one GaO4 tetrahedra, corners with two equivalent GaO4 trigonal pyramids, edges with two equivalent PrO6 octahedra, an edgeedge with one GaO4 tetrahedra, and an edgeedge with one GaO4 trigonal pyramid. There are a spread of Pr–O bond distances ranging from 2.37–2.62 Å. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 trigonal pyramids that share corners with two equivalent PrO7 hexagonal pyramids, corners with two equivalent PrO6 octahedra, a cornercorner with one GaO4 tetrahedra, and an edgeedge with one PrO7 hexagonal pyramid. The corner-sharing octahedra tilt angles range from 40–54°. There are a spread of Ga–O bond distances ranging from 1.83–1.89 Å. In the second Ga3+ site, Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share a cornercorner with one PrO7 hexagonal pyramid, corners with three equivalent PrO6 octahedra, a cornercorner with one GaO4 trigonal pyramid, and an edgeedge with one PrO7 hexagonal pyramid. The corner-sharing octahedra tilt angles range from 50–61°. There are a spread of Ga–O bond distances ranging from 1.83–1.89 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded to three Pr3+ and one Ga3+ atom to form distorted OPr3Ga trigonal pyramids that share corners with three OPr2Ga2 tetrahedra and edges with three OPr4 tetrahedra. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Pr3+ and one Ga3+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to three Pr3+ and one Ga3+ atom. In the fourth O2- site, O2- is bonded to two Pr3+ and two Ga3+ atoms to form a mixture of distorted edge and corner-sharing OPr2Ga2 tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to three Pr3+ and one Ga3+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to three Pr3+ and one Ga3+ atom. In the seventh O2- site, O2- is bonded to three Pr3+ and one Ga3+ atom to form distorted OPr3Ga tetrahedra that share corners with six OPr2Ga2 tetrahedra, an edgeedge with one OPr2Ga2 tetrahedra, and an edgeedge with one OPr3Ga trigonal pyramid. In the eighth O2- site, O2- is bonded to four Pr3+ atoms to form OPr4 tetrahedra that share corners with six OPr2Ga2 tetrahedra, edges with three OPr2Ga2 tetrahedra, and an edgeedge with one OPr3Ga trigonal pyramid. In the ninth O2- site, O2- is bonded to four Pr3+ atoms to form OPr4 tetrahedra that share corners with five OPr2Ga2 tetrahedra, a cornercorner with one OPr3Ga trigonal pyramid, edges with two OPr4 tetrahedra, and an edgeedge with one OPr3Ga trigonal pyramid.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr4Si2S3O7 by Materials Project

Pr4Si2S3O7 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. there are two inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 9-coordinate geometry to three S2- and six O2- atoms. There are one shorter (2.93 Å) and two longer (2.97 Å) Pr–S bond lengths. There are a spread of Pr–O bond distances ranging from 2.52–2.64 Å. In the second Pr3+ site, Pr3+ is bonded in a 6-coordinate geometry to three S2- and three O2- atoms. There are two shorter (2.89 Å) and one longer (2.91 Å) Pr–S bond lengths. There are one shorter (2.42 Å) and two longer (2.54 Å) Pr–O bond lengths. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SPr4O2 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 65°. There are a spread of Si–O bond distances ranging from 1.64–1.66 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted square co-planar geometry to four equivalent Pr3+ atoms. In the second S2- site, S2- is bonded to four equivalent Pr3+ and two equivalent O2- atoms to form distorted SPr4O2 octahedra that share corners with four equivalent SiO4 tetrahedra. Both S–O bond lengths are 3.29 Å. In the third S2- site, S2- is bonded in a 4-coordinate geometry to four Pr3+ atoms. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Si4+ and one S2- atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to three Pr3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrMgPt by Materials Project

MgPrPt crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Mg is bonded in a 4-coordinate geometry to four Pt atoms. There are two shorter (2.77 Å) and two longer (2.96 Å) Mg–Pt bond lengths. Pr is bonded in a 5-coordinate geometry to five Pt atoms. There are four shorter (3.10 Å) and one longer (3.14 Å) Pr–Pt bond lengths. There are two inequivalent Pt sites. In the first Pt site, Pt is bonded in a 9-coordinate geometry to six equivalent Mg and three equivalent Pr atoms. In the second Pt site, Pt is bonded in a 9-coordinate geometry to three equivalent Mg and six equivalent Pr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr2SiTeO4 by Materials Project

Pr2SiTeO4 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are two inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 6-coordinate geometry to four equivalent Te2- and six O2- atoms. There are two shorter (3.39 Å) and two longer (3.71 Å) Pr–Te bond lengths. There are two shorter (2.55 Å) and four longer (2.56 Å) Pr–O bond lengths. In the second Pr3+ site, Pr3+ is bonded in a 6-coordinate geometry to three equivalent Te2- and six O2- atoms. There are a spread of Pr–Te bond distances ranging from 3.21–3.41 Å. There are a spread of Pr–O bond distances ranging from 2.50–2.64 Å. Si4+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.65 Å) and two longer (1.67 Å) Si–O bond length. Te2- is bonded in a 1-coordinate geometry to seven Pr3+ and ten O2- atoms. There are a spread of Te–O bond distances ranging from 3.36–3.74 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to three Pr3+, one Si4+, and three equivalent Te2- atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three Pr3+, one Si4+, and two equivalent Te2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrIn by Materials Project

Pr(In) is Tetraauricupride structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pr is bonded in a body-centered cubic geometry to eight equivalent In atoms. All Pr–In bond lengths are 3.38 Å. In is bonded in a body-centered cubic geometry to eight equivalent Pr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrAl4 by Materials Project

PrAl4 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Pr is bonded in a 8-coordinate geometry to sixteen Al atoms. There are eight shorter (3.29 Å) and eight longer (3.56 Å) Pr–Al bond lengths. There are two inequivalent Al sites. In the first Al site, Al is bonded in a 9-coordinate geometry to four equivalent Pr and five Al atoms. There are one shorter (2.54 Å) and four longer (2.66 Å) Al–Al bond lengths. In the second Al site, Al is bonded to four equivalent Pr and eight Al atoms to form a mixture of distorted face, edge, and corner-sharing AlPr4Al8 cuboctahedra. All Al–Al bond lengths are 3.04 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrNi5 by Materials Project

PrNi5 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Pr is bonded in a 6-coordinate geometry to eighteen Ni atoms. There are six shorter (2.87 Å) and twelve longer (3.18 Å) Pr–Ni bond lengths. There are two inequivalent Ni sites. In the first Ni site, Ni is bonded in a 12-coordinate geometry to three equivalent Pr and six equivalent Ni atoms. All Ni–Ni bond lengths are 2.45 Å. In the second Ni site, Ni is bonded to four equivalent Pr and eight Ni atoms to form a mixture of corner, edge, and face-sharing NiPr4Ni8 cuboctahedra. All Ni–Ni bond lengths are 2.49 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrCu5 by Materials Project

PrCu5 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Pr is bonded in a 6-coordinate geometry to eighteen Cu atoms. There are six shorter (2.96 Å) and twelve longer (3.29 Å) Pr–Cu bond lengths. There are two inequivalent Cu sites. In the first Cu site, Cu is bonded in a 12-coordinate geometry to three equivalent Pr and six equivalent Cu atoms. All Cu–Cu bond lengths are 2.53 Å. In the second Cu site, Cu is bonded to four equivalent Pr and eight Cu atoms to form a mixture of face, edge, and corner-sharing CuPr4Cu8 cuboctahedra. All Cu–Cu bond lengths are 2.57 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PrCo5 by Materials Project

PrCo5 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Pr is bonded in a 6-coordinate geometry to eighteen Co atoms. There are six shorter (2.91 Å) and twelve longer (3.20 Å) Pr–Co bond lengths. There are two inequivalent Co sites. In the first Co site, Co is bonded in a 12-coordinate geometry to three equivalent Pr and six equivalent Co atoms. All Co–Co bond lengths are 2.45 Å. In the second Co site, Co is bonded to four equivalent Pr and eight Co atoms to form a mixture of edge, face, and corner-sharing CoPr4Co8 cuboctahedra. All Co–Co bond lengths are 2.52 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr4Se3N2 by Materials Project

Pr4N2Se3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded in a 2-coordinate geometry to two equivalent N3- and four Se2- atoms. There are one shorter (2.36 Å) and one longer (2.40 Å) Pr–N bond lengths. There are a spread of Pr–Se bond distances ranging from 3.04–3.07 Å. In the second Pr3+ site, Pr3+ is bonded in a 2-coordinate geometry to two equivalent N3- and five Se2- atoms. There are one shorter (2.34 Å) and one longer (2.37 Å) Pr–N bond lengths. There are a spread of Pr–Se bond distances ranging from 3.16–3.36 Å. N3- is bonded to four Pr3+ atoms to form NPr4 tetrahedra that share corners with eight SePr6 octahedra, corners with two equivalent NPr4 tetrahedra, edges with five SePr6 octahedra, and an edgeedge with one NPr4 tetrahedra. The corner-sharing octahedra tilt angles range from 25–81°. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to six Pr3+ atoms to form distorted SePr6 octahedra that share corners with seven SePr6 octahedra, corners with six equivalent NPr4 tetrahedra, edges with six equivalent SePr6 octahedra, edges with three equivalent NPr4 tetrahedra, and a faceface with one SePr6 octahedra. The corner-sharing octahedra tilt angles range from 19–63°. In the second Se2- site, Se2- is bonded to six Pr3+ atoms to form distorted SePr6 octahedra that share corners with ten equivalent SePr6 octahedra, corners with four equivalent NPr4 tetrahedra, edges with two equivalent SePr6 octahedra, edges with four equivalent NPr4 tetrahedra, and faces with two equivalent SePr6 octahedra. The corner-sharing octahedra tilt angles range from 29–63°.

36 MATERIALS SCIENCE↗