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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on K2U(Si2O5)3 by Materials Project

K2U(Si2O5)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.91–3.46 Å. In the second K1+ site, K1+ is bonded in a 3-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.80–3.46 Å. U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of U–O bond distances ranging from 2.21–2.30 Å. There are six inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 28°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 34°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 42°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one U4+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent K1+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two K1+, one U4+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to two K1+, one U4+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one U4+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one U4+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourteenth O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one U4+, and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb2U(Si2O5)3 by Materials Project

Rb2U(Si2O5)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Rb1+ sites. In the first Rb1+ site, Rb1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Rb–O bond distances ranging from 3.03–3.41 Å. In the second Rb1+ site, Rb1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Rb–O bond distances ranging from 2.94–3.45 Å. U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of U–O bond distances ranging from 2.22–2.28 Å. There are six inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 30°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 24°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 29°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 43°. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Rb1+, one U4+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Rb1+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Rb1+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Rb1+ and two Si4+ atoms. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two Rb1+, one U4+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Rb1+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, one U4+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, one U4+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Rb1+ and two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, one U4+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourteenth O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Rb1+, one U4+, and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

CLASSY IV. Exploring UV Diagnostics of the Interstellar Medium in Local High- z Analogs at the Dawn of the JWST Era

The Cosmic Origins Spectrograph (COS) Legacy Archive Spectroscopic SurveY (CLASSY) provides the first high resolution spectral catalog of 45 local high-z analogs in the ultraviolet (UV; 1200–2000 Å) to investigate their stellar and gas properties. Here we present a toolkit of UV interstellar medium (ISM) diagnostics, analyzing the main emission lines of CLASSY spectra (N IV] λλ1483,87, C IV λλ1548,51, He IIλ1640, O III]λλ1661,6, Si III] λλ1883,92, C III] λ1907,9). Specifically, our aim is to provide accurate diagnostics for the reddening E(B - V), electron density n e , electron temperature T e , metallicity 12+log(O/H), and ionization parameter log(U), taking the different ISM ionization zones into account. We calibrate our UV toolkit using well-known optical diagnostics, analyzing archival optical spectra for all CLASSY targets. We find that UV density diagnostics estimate n e values that are ~1–2 dex higher (e.g., n e (C III] λλ1907,9) ~ 10 4 cm -3 ) than those inferred from their optical counterparts (e.g., n e ([S II]λλ6717,31) ~ 10 2 cm -3 ; n e ([Ar IV]λλ4714,41) ~ 10 3 cm -3 ). T e derived from the hybrid ratio [O III] λ1666/λ5007 proves to be reliable, implying differences in determining 12+log(O/H) compared to the optical counterpart O III] λ4363/[O III] λ5007 within ~ ±0.3 dex. We also investigate the relation between the stellar and gas E(B - V), finding consistent values at high specific star formation rates (sSFRs; log sSFR ≳ -8 yr -1 ), while at low sSFRs we confirmed an excess of dust attenuation in the gas. Finally, we investigate UV line ratios and equivalent widths to provide correlations with 12+log (O/H) and log(U), but note that there are degeneracies between the two. With this suite of UV-based diagnostics, we illustrate the pivotal role CLASSY plays in understanding the chemical and physical properties of high-z systems that JWST can observe in the rest-frame UV.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Materials Data on Cs2U(Si2O5)3 by Materials Project

Cs2U(Si2O5)3 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 11-coordinate geometry to eleven O2- atoms. There are a spread of Cs–O bond distances ranging from 3.32–3.71 Å. In the second Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Cs–O bond distances ranging from 3.23–3.44 Å. U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of U–O bond distances ranging from 2.24–2.28 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 33°. There are a spread of Si–O bond distances ranging from 1.60–1.64 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Si–O bond distances ranging from 1.62–1.64 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 34°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 29°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Cs1+, one U4+, and one Si4+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Si4+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Cs1+, one U4+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two equivalent Si4+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+, one U4+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cs1+ and two equivalent Si4+ atoms. In the tenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cs1+ and two Si4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Diastereoselective Template Synthesis on Iron and Uranium

The addition of 2 equiv of t Bu 2 PSiMe 3 to 2,6-pyridinedicarboxaldehyde ((CHO) 2 Py) results in a rac / meso diastereomeric mixture of the PNP-chelating ligand 2,6-bis((trimethylsiloxy)(di- tert -butylphosphino)-methyl)-pyridine ( (OTMS) PNP t Bu ) ( 1 - r / m ) via addition of the P–Si bond across both of the aldehyde C–O bonds. Chelation of (OTMS) PNP t Bu to FeCl 2 results in the same diastereotopic ratio of ( (OTMS) PNP t Bu )FeCl 2 ( 2- r / m ) as the free ligand. Fractional crystallization allows for the isolation of the C 2 isomer, 2- r , and a template synthesis protocol allows for the synthesis and isolation of the C s isomer, 2- m , in good yield. Furthermore, the template synthesis protocol was also expanded to the f -block with the use of UCl 4 in order to assess the specificity of the template synthesis on a larger metal cation. This reaction performed on UCl 4 forms the meso diastereospecific uranium complex ( ( t Bu2P) ONO)UCl 2 (dtbpy), 3 - m , with observation of the rational intermediate ( (OTMS) PNO t Bu )UCl 3 (dtbpy), 4 - m , which arose from the respective formation of two- or one-equivalents of TMS–Cl and formation of the corresponding U–O bond.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on CaU2Si2(HO3)4 by Materials Project

CaU2Si2(HO3)4 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. Ca2+ is bonded in a 6-coordinate geometry to two H1+ and four O2- atoms. There are one shorter (2.49 Å) and one longer (2.58 Å) Ca–H bond lengths. There are a spread of Ca–O bond distances ranging from 2.18–2.58 Å. There are two inequivalent U5+ sites. In the first U5+ site, U5+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share corners with three equivalent SiO4 tetrahedra, edges with two equivalent UO7 pentagonal bipyramids, and an edgeedge with one SiO4 tetrahedra. There are a spread of U–O bond distances ranging from 1.83–2.55 Å. In the second U5+ site, U5+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share corners with three equivalent SiO4 tetrahedra, edges with two equivalent UO7 pentagonal bipyramids, and an edgeedge with one SiO4 tetrahedra. There are a spread of U–O bond distances ranging from 1.80–2.55 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent UO7 pentagonal bipyramids and an edgeedge with one UO7 pentagonal bipyramid. There are a spread of Si–O bond distances ranging from 1.61–1.72 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent UO7 pentagonal bipyramids and an edgeedge with one UO7 pentagonal bipyramid. There are a spread of Si–O bond distances ranging from 1.57–1.73 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one Ca2+ atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one Ca2+ atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one U5+, one Si4+, and one H1+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Ca2+ and one Si4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent U5+ and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent U5+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted linear geometry to one U5+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Si4+, and one H1+ atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one U5+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one U5+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one U5+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent U5+ and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Ca2+ and one U5+ atom. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent U5+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Laser Plasma Interaction in the MG Magnetic Field (Final Report)

Strong magnetic fields change properties of plasma. Employment of the magnetic fields can improve conditions for inertial confinement fusion. Compression and heating of the magnetized plasma is a base of the MagLIF pulsed power approach to the controlled fusion. Study of expansion and heating of plasma in the external magnetic fields, development of plasma instabilities, parametric and other effects are important for basic physics and applications. The main goal of the research for the grant was experimental investigation of laser produced plasma in the well characterized and controlled MG magnetic fields. We developed a platform for investigation of high intensity laser-plasma interaction (LPI) in the MG fields using a university-scale pulsed power machine. A Zebra machine at UNR generated transverse magnetic fields of 3 MG on the surface of the rod load and longitudinal fields of 1.4 MG in the coil loads. The magnetic fields were characterized with two-color Faraday rotation diagnostics. The pulsed power machine provided almost static magnetic fields for LPI compared to the much faster laser driven magnetic fields. We found that eddy currents in the rising magnetic field generate plasma on the metal targets. Eddy currents did not impact Si and CH dielectric targets. A Leopard laser with intensity in the focus up to 10 19 W/cm 2 produced plasma in the MG magnetic fields. The modified reflected Faraday diagnostics was used to study laser driven B-field at the MTW laser at Laboratory for Laser Energetics, UR. We demonstrated a slow dependence of the magnetic field in the coil on the applied laser intensity. The magnetic field increased by a factor of 2 if laser intensity increased by a factor of 30. This scaling is important for comparison of experiments at different laser facilities. Expansion of the plasma in the 2-3 MG external B-field was studied. Laser-produced plasma in the azimuthal magnetic field took the unique form of a thin disc expanding radially with a velocity of 250 km/s and confined in the vertical direction. A HYDRA MHD program at the University of Rochester was applied for simulations of LPI in the magnetic field B >3 MG. Simulations for the plasma disc parameters and the expansion dynamics were in a good agreement with experiments. Generation of narrow dense plasma jets in the longitudinal magnetic field of 0.6-0.8 MG was studied. Narrow plasma jets reached a length of 3-4 mm with the electron plasma density of (0.2-1.2)x10 20 cm -3 . A jet tip propagated with the velocity of 160-200 km/s. MHD simulations showed a good agreement of the dynamics of the formation of plasma jets with experiments. These jets are relevant to astrophysical jets. Simulations of K-shell spectra of Si plasma was performed for LPI in the B-field. The laser prepulse generated plasma near the laser target. A PrismSPECT model with a MeV electron beam produced by the laser was used. The spectral modelling showed the increased plasma density by a factor by 2-3 in the magnetic field. This was in agreement with the observed dynamics of the plasma plume confined by the axial magnetic field. The two-plasmon decay was studied in the 2.5-3 MG transversal magnetic fields. Strong 2-3.5 nm spectral widening and a 2-4 nm shifts of “red” and “blue” 3/2ω 0 spectral components were observed. The large shift and widening exceed the expected temperature and magnetic shift. PIC simulations are performing to clarify physics of this effect. The experimental research program for the grant is completed. New plasma effects in the MG fields were studied at the university-scale pulsed power generator. Two graduate and two undergraduate UNR and UR students carried experiments at the Zebra generator, supported and developed plasma diagnostics, provided data processing, and performed MHD simulations of LPI in the strong magnetic field. Research results are published in 9 referred papers and presented in 12 conferences. Program manager: Kramer U. Akli; Collaborators: R. C. Mancini and H. Sawada, University of Nevada, Reno (UNR); R. Betti and A. V. Maximov, University of Rochester (UR).

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2021

Mechanical Design Progress of the In Situ Nanoprobe Instrument for APS-U

The In Situ Nanoprobe (ISN, 19-ID) beamline will be a new best-in-class long beamline to be constructed as part of the Advanced Photon Source Upgrade (APS-U) project [1, 2]. To achieve long working distance at high spatial resolution, the ISN instrument will be positioned 210 m downstream of the x-ray source, in a dedicated satellite building, currently under construction [3]. The ISN instrument will use a nano-focusing Kirkpatrick-Baez (K-B) mirror system, which will focus hard x-rays to a focal spot as small as 20 nm, with a large working distance of 61 mm. The large working distance provides space for various in situ sample cells for x-ray fluorescence tomography and ptychographic 3D imaging, allows the use of a separate, independent vacuum chambers for the optics and sample, and provides the flexibility to run experiments in vacuum or at ambient pressure. A consequence of the small spot size and large working distance are stringent requirements for high angular stability of the K-B mirrors (5 nrad V-mirror and 16 nrad H-mirror) and high relative stability be-tween focus spot and sample (4 nmRMS). Additional features include fly-scanning up to 2 kg mass, sample plus in situ cell, at 1 mm/s in vertical and/or horizontal directions over an area of 10 mm x 10 mm. Environmental capabili-ties will include heating and cooling, flow of fluids and applied fields, as required for electrochemistry and flow of gases at high temperature for catalysis. To achieve these capabilities and precise requirements we have used precision engineering fundamentals to guide the design process.

Kearney, Steven P.↗
DOE OSTI2021

Cryo-EM model validation recommendations based on outcomes of the 2019 EMDataResource challenge

This paper describes outcomes of the 2019 Cryo-EM Model Challenge. The goals were to (1) assess the quality of models that can be produced from cryogenic electron microscopy (cryo-EM) maps using current modeling software, (2) evaluate reproducibility of modeling results from different software developers and users and (3) compare performance of current metrics used for model evaluation, particularly Fit-to-Map metrics, with focus on near-atomic resolution. Our findings demonstrate the relatively high accuracy and reproducibility of cryo-EM models derived by 13 participating teams from four benchmark maps, including three forming a resolution series (1.8 to 3.1 Å). The results permit specific recommendations to be made about validating near-atomic cryo-EM structures both in the context of individual experiments and structure data archives such as the Protein Data Bank. We recommend the adoption of multiple scoring parameters to provide full and objective annotation and assessment of the model, reflective of the observed cryo-EM map density.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Materials Data on CaU2Si2(HO3)4 by Materials Project

(CaU2Si2(HO4)3)2H2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of four hydrogen molecules and one CaU2Si2(HO4)3 framework. In the CaU2Si2(HO4)3 framework, Ca2+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Ca–O bond distances ranging from 2.15–2.33 Å. There are two inequivalent U5+ sites. In the first U5+ site, U5+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share corners with three SiO4 tetrahedra, edges with two equivalent UO7 pentagonal bipyramids, and an edgeedge with one SiO4 tetrahedra. There are a spread of U–O bond distances ranging from 1.83–2.60 Å. In the second U5+ site, U5+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share corners with three SiO4 tetrahedra, edges with two equivalent UO7 pentagonal bipyramids, and an edgeedge with one SiO4 tetrahedra. There are a spread of U–O bond distances ranging from 1.86–2.54 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three UO7 pentagonal bipyramids and an edgeedge with one UO7 pentagonal bipyramid. There are a spread of Si–O bond distances ranging from 1.62–1.69 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three UO7 pentagonal bipyramids and an edgeedge with one UO7 pentagonal bipyramid. There are a spread of Si–O bond distances ranging from 1.58–1.73 Å. There are three inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Ca2+ and one U5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one U5+, one Si4+, and one H1+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one U5+, one Si4+, and one H1+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two U5+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ca2+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to two U5+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two U5+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to one U5+ atom. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to two U5+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ca2+ and one U5+ atom. In the eleventh O2- site, O2- is bonded in a bent 120 degrees geometry to one Si4+ and one H1+ atom. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ca2+ and one U5+ atom.

36 MATERIALS SCIENCE↗