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DOE OSTI2020

Materials Data on Lu20Os5I24 by Materials Project

Lu20Os5I24 crystallizes in the triclinic P-1 space group. The structure is one-dimensional and consists of one Lu20Os5I24 ribbon oriented in the (1, 1, 1) direction. there are ten inequivalent Lu sites. In the first Lu site, Lu is bonded in a 5-coordinate geometry to two Os and four I atoms. There are one shorter (2.82 Å) and one longer (2.92 Å) Lu–Os bond lengths. There are a spread of Lu–I bond distances ranging from 3.05–3.79 Å. In the second Lu site, Lu is bonded in a 5-coordinate geometry to two Os and four I atoms. There are one shorter (2.84 Å) and one longer (2.92 Å) Lu–Os bond lengths. There are a spread of Lu–I bond distances ranging from 3.06–3.86 Å. In the third Lu site, Lu is bonded in a 6-coordinate geometry to two Os and four I atoms. Both Lu–Os bond lengths are 2.84 Å. There are a spread of Lu–I bond distances ranging from 3.12–3.44 Å. In the fourth Lu site, Lu is bonded to two Os and three I atoms to form distorted corner-sharing LuOs2I3 trigonal bipyramids. There are one shorter (2.84 Å) and one longer (2.93 Å) Lu–Os bond lengths. There are one shorter (3.05 Å) and two longer (3.14 Å) Lu–I bond lengths. In the fifth Lu site, Lu is bonded in a 5-coordinate geometry to two Os and four I atoms. There are one shorter (2.82 Å) and one longer (2.90 Å) Lu–Os bond lengths. There are a spread of Lu–I bond distances ranging from 3.06–3.83 Å. In the sixth Lu site, Lu is bonded in a 5-coordinate geometry to two Os and four I atoms. There are one shorter (2.83 Å) and one longer (2.84 Å) Lu–Os bond lengths. There are a spread of Lu–I bond distances ranging from 3.11–3.70 Å. In the seventh Lu site, Lu is bonded in a 6-coordinate geometry to two Os and four I atoms. Both Lu–Os bond lengths are 2.81 Å. There are a spread of Lu–I bond distances ranging from 3.11–3.56 Å. In the eighth Lu site, Lu is bonded in a 6-coordinate geometry to two Os and four I atoms. There are one shorter (2.80 Å) and one longer (2.81 Å) Lu–Os bond lengths. There are a spread of Lu–I bond distances ranging from 3.10–3.64 Å. In the ninth Lu site, Lu is bonded in a 6-coordinate geometry to two equivalent Os and four I atoms. Both Lu–Os bond lengths are 2.80 Å. There are a spread of Lu–I bond distances ranging from 3.10–3.41 Å. In the tenth Lu site, Lu is bonded in a 6-coordinate geometry to two equivalent Os and four I atoms. There are one shorter (2.82 Å) and one longer (2.83 Å) Lu–Os bond lengths. There are a spread of Lu–I bond distances ranging from 3.11–3.33 Å. There are three inequivalent Os sites. In the first Os site, Os is bonded in a body-centered cubic geometry to eight Lu atoms. In the second Os site, Os is bonded in a 8-coordinate geometry to eight Lu atoms. In the third Os site, Os is bonded in a 8-coordinate geometry to eight Lu atoms. There are twelve inequivalent I sites. In the first I site, I is bonded in a 2-coordinate geometry to two Lu atoms. In the second I site, I is bonded in a 2-coordinate geometry to two Lu atoms. In the third I site, I is bonded in a 3-coordinate geometry to three Lu atoms. In the fourth I site, I is bonded in a 3-coordinate geometry to three Lu atoms. In the fifth I site, I is bonded in a 3-coordinate geometry to three Lu atoms. In the sixth I site, I is bonded in a 3-coordinate geometry to three Lu atoms. In the seventh I site, I is bonded in a 4-coordinate geometry to four Lu atoms. In the eighth I site, I is bonded in a 4-coordinate geometry to four Lu atoms. In the ninth I site, I is bonded in a 4-coordinate geometry to four Lu atoms. In the tenth I site, I is bonded in a 4-coordinate geometry to four Lu atoms. In the eleventh I site, I is bonded in a 4-coordinate geometry to four Lu atoms. In the twelfth I site, I is bonded in a 4-coordinate geometry to three Lu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

The QUIC Start Guide (v 6.4.7)

There are versions of QUIC for 64-bit Windows, 64-bit Linux, and 64-bit Intel Mac OS X. As compared to earlier 32-bit versions of QUIC, the 64-bit versions allow the QUIC transport and dispersion codes to access greater than 2 GB of RAM and thus larger problems can be run.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS2009

Solubility of Sulfur in Shergottitic Silicate Melts Up to 0.8 GPA: Implications for S Contents of Shergottites

Shergottites have high S contents (1300 to 4600 ppm; [1]), but it is unclear if they are sulfide saturated or under-saturated. This issue has fundamental implications for determining the long term S budget of the martian surface and atmosphere (from mantle degassing), as well as evolution of the highly siderophile elements (HSE) Au, Pd, Pt, Re, Rh, Ru, Ir, and Os, since concentrations of the latter are controlled by sulfide stability. Resolution of sulfide saturation depends upon temperature, pressure, oxygen fugacity (and FeO), and magma composition [2]. Expressions derived from experimental studies allow prediction of S contents, though so far they are not calibrated for shergottitic liquids [3-5]. We have carried out new experiments designed to test current S saturation models, and then show that existing calibrations are not suitable for high FeO and low Al2O3 compositions characteristic of shergottitic liquids. The new results show that existing models underpredict S contents of sulfide saturated shergottitic liquids by a factor of 2.

Righter, K.↗
DOE OSTI2020

Materials Data on Ag13OsO6 by Materials Project

Ag13OsO6 crystallizes in the cubic Fm-3c space group. The structure is three-dimensional. Os1- is bonded in an octahedral geometry to six equivalent O2- atoms. All Os–O bond lengths are 1.92 Å. There are two inequivalent Ag1+ sites. In the first Ag1+ site, Ag1+ is bonded in a cuboctahedral geometry to twelve equivalent Ag1+ atoms. All Ag–Ag bond lengths are 2.84 Å. In the second Ag1+ site, Ag1+ is bonded in a 2-coordinate geometry to one Ag1+ and two equivalent O2- atoms. Both Ag–O bond lengths are 2.51 Å. O2- is bonded in a 1-coordinate geometry to one Os1- and four equivalent Ag1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Y(III) Sorption at the Orthoclase (001) Surface Measured by X-ray Reflectivity

Interactions of heavy metals with charged mineral surfaces control their mobility in the environment. Here, we investigate the adsorption of Y(III) onto the orthoclase (001) basal plane, the former as a representative of rare earth elements and an analogue of trivalent actinides and the latter as a representative of naturally abundant K-feldspar minerals. In this study, we apply in situ high-resolution X-ray reflectivity to determine the sorption capacity and molecular distribution of adsorbed Y species as a function of the Y 3+ concentration, [Y 3+ ], at pH 7 and 5. With [Y 3+ ] ≥ 1 mM at pH 7, we observe an inner-sphere (IS) sorption complex at a distance of ~1.5 Å from the surface and an outer-sphere (OS) complex at 3–4 Å. Based on the adsorption height of the IS complex, a bidentate, binuclear binding mode, in which Y 3+ binds to two terminal oxygens, is proposed. In contrast, mostly OS sorption is observed at pH 5. The observed maximum Y coverage is ~1.3 Y 3+ /A UC (A UC : area of the unit cell = 111.4 Å 2 ) for all the investigated pH values and Y concentrations, which is in the expected range based on the estimated surface charge of orthoclase (001).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2005

Towards the Development of a Unified Distributed Date System for L1 Spacecraft

The purpose of this grant, 'Towards the Development of a Unified Distributed Data System for L1 Spacecraft', is to take the initial steps towards the development of a data distribution mechanism for making in-situ measurements more easily accessible to the scientific community. Our obligations as subcontractors to this grant are to add our Faraday Cup plasma data to this initial study and to contribute to the design of a general data distribution system. The year 1 objectives of the overall project as stated in the GSFC proposal are: 1) Both the rsync and Perl based data exchange tools will be fully developed and tested in our mixed, Unix, VMS, Windows and Mac OS X data service environment. Based on the performance comparisons, one will be selected and fully deployed. Continuous data exchange between all L1 solar wind monitors initiated. 2) Data version metadata will be agreed upon, fully documented, and deployed on our data sites. 3) The first version of the data description rules, encoded in a XML Schema, will be finalized. 4) Preliminary set of library routines will be collected, documentation standards and formats agreed on, and desirable routines that have not been implemented identified and assigned. 5) ViSBARD test site implemented to independently validate data mirroring procedures. The specific MIT tasks over the duration of this project are the following: a) implement mirroring service for WIND plasma data b) participate in XML Schema development c) contribute toward routine library.

Lazarus, Alan J.↗
DOE OSTI2020

Materials Data on Tl2OsCBr2OF3 by Materials Project

Os2Tl4COBr4F6CO crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of four formaldehyde molecules and one Os2Tl4COBr4F6 sheet oriented in the (-1, 0, 2) direction. In the Os2Tl4COBr4F6 sheet, there are two inequivalent Os1+ sites. In the first Os1+ site, Os1+ is bonded in a 5-coordinate geometry to two Br1- and three F1- atoms. There are one shorter (2.48 Å) and one longer (2.49 Å) Os–Br bond lengths. There are two shorter (2.02 Å) and one longer (2.12 Å) Os–F bond lengths. In the second Os1+ site, Os1+ is bonded in a 5-coordinate geometry to two Br1- and three F1- atoms. Both Os–Br bond lengths are 2.48 Å. There are a spread of Os–F bond distances ranging from 2.02–2.10 Å. There are four inequivalent Tl1+ sites. In the first Tl1+ site, Tl1+ is bonded in a 4-coordinate geometry to four F1- atoms. There are a spread of Tl–F bond distances ranging from 2.66–2.97 Å. In the second Tl1+ site, Tl1+ is bonded in a 6-coordinate geometry to six F1- atoms. There are a spread of Tl–F bond distances ranging from 2.76–3.10 Å. In the third Tl1+ site, Tl1+ is bonded in a 2-coordinate geometry to two F1- atoms. Both Tl–F bond lengths are 2.91 Å. In the fourth Tl1+ site, Tl1+ is bonded in a 1-coordinate geometry to one O2- and four F1- atoms. The Tl–O bond length is 3.19 Å. There are a spread of Tl–F bond distances ranging from 2.67–2.98 Å. C4+ is bonded in a single-bond geometry to one O2- atom. The C–O bond length is 1.18 Å. O2- is bonded in a distorted single-bond geometry to one Tl1+ and one C4+ atom. There are four inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a distorted single-bond geometry to one Os1+ atom. In the second Br1- site, Br1- is bonded in a distorted single-bond geometry to one Os1+ atom. In the third Br1- site, Br1- is bonded in a 1-coordinate geometry to one Os1+ atom. In the fourth Br1- site, Br1- is bonded in a 1-coordinate geometry to one Os1+ atom. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a 4-coordinate geometry to one Os1+ and three Tl1+ atoms. In the second F1- site, F1- is bonded in a distorted single-bond geometry to one Os1+ and three Tl1+ atoms. In the third F1- site, F1- is bonded in a 1-coordinate geometry to one Os1+ and three Tl1+ atoms. In the fourth F1- site, F1- is bonded in a 1-coordinate geometry to one Os1+ and three Tl1+ atoms. In the fifth F1- site, F1- is bonded in a 1-coordinate geometry to one Os1+ and two equivalent Tl1+ atoms. In the sixth F1- site, F1- is bonded in a distorted trigonal non-coplanar geometry to one Os1+ and two Tl1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K15Os7N19 by Materials Project

K15Os7N19 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are sixteen inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 4-coordinate geometry to four N3- atoms. There are a spread of K–N bond distances ranging from 2.77–2.91 Å. In the second K1+ site, K1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of K–N bond distances ranging from 2.79–3.08 Å. In the third K1+ site, K1+ is bonded to four N3- atoms to form distorted KN4 tetrahedra that share corners with four OsN4 tetrahedra and an edgeedge with one KN6 pentagonal pyramid. There are a spread of K–N bond distances ranging from 2.71–3.05 Å. In the fourth K1+ site, K1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of K–N bond distances ranging from 2.67–3.34 Å. In the fifth K1+ site, K1+ is bonded in a 4-coordinate geometry to four N3- atoms. There are a spread of K–N bond distances ranging from 2.68–2.83 Å. In the sixth K1+ site, K1+ is bonded in a 4-coordinate geometry to five N3- atoms. There are a spread of K–N bond distances ranging from 2.74–3.34 Å. In the seventh K1+ site, K1+ is bonded to six N3- atoms to form distorted KN6 pentagonal pyramids that share corners with two OsN4 tetrahedra, an edgeedge with one KN6 pentagonal pyramid, an edgeedge with one KN4 tetrahedra, and edges with three OsN4 tetrahedra. There are a spread of K–N bond distances ranging from 2.73–2.97 Å. In the eighth K1+ site, K1+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of K–N bond distances ranging from 2.72–3.10 Å. In the ninth K1+ site, K1+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of K–N bond distances ranging from 2.82–3.01 Å. In the tenth K1+ site, K1+ is bonded in a 5-coordinate geometry to five N3- atoms. There are a spread of K–N bond distances ranging from 2.67–3.34 Å. In the eleventh K1+ site, K1+ is bonded in a 3-coordinate geometry to six N3- atoms. There are a spread of K–N bond distances ranging from 2.65–3.45 Å. In the twelfth K1+ site, K1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of K–N bond distances ranging from 2.82–3.29 Å. In the thirteenth K1+ site, K1+ is bonded in a 3-coordinate geometry to five N3- atoms. There are a spread of K–N bond distances ranging from 2.72–3.25 Å. In the fourteenth K1+ site, K1+ is bonded in a 4-coordinate geometry to four N3- atoms. There are a spread of K–N bond distances ranging from 2.59–2.97 Å. In the fifteenth K1+ site, K1+ is bonded to eight N3- atoms to form distorted KN8 hexagonal bipyramids that share corners with two equivalent OsN4 tetrahedra and edges with six OsN4 tetrahedra. There are a spread of K–N bond distances ranging from 2.83–3.49 Å. In the sixteenth K1+ site, K1+ is bonded in a 6-coordinate geometry to six N3- atoms. There are a spread of K–N bond distances ranging from 2.90–3.33 Å. There are seven inequivalent Os6+ sites. In the first Os6+ site, Os6+ is bonded to four N3- atoms to form OsN4 tetrahedra that share a cornercorner with one KN6 pentagonal pyramid, a cornercorner with one KN4 tetrahedra, corners with three OsN4 tetrahedra, and an edgeedge with one KN6 pentagonal pyramid. There are a spread of Os–N bond distances ranging from 1.79–1.99 Å. In the second Os6+ site, Os6+ is bonded to four N3- atoms to form OsN4 tetrahedra that share corners with three OsN4 tetrahedra and an edgeedge with one KN8 hexagonal bipyramid. There are a spread of Os–N bond distances ranging from 1.81–1.92 Å. In the third Os6+ site, Os6+ is bonded to four N3- atoms to form OsN4 tetrahedra that share a cornercorner with one KN8 hexagonal bipyramid, corners with three OsN4 tetrahedra, and an edgeedge with one KN8 hexagonal bipyramid. There are a spread of Os–N bond distances ranging from 1.77–2.01 Å. In the fourth Os6+ site, Os6+ is bonded to four N3- atoms to form OsN4 tetrahedra that share corners with two OsN4 tetrahedra and an edgeedge with one KN8 hexagonal bipyramid. There are a spread of Os–N bond distances ranging from 1.81–1.89 Å. In the fifth Os6+ site, Os6+ is bonded to four N3- atoms to form corner-sharing OsN4 tetrahedra. There are a spread of Os–N bond distances ranging from 1.77–1.96 Å. In the sixth Os6+ site, Os6+ is bonded to four N3- atoms to form OsN4 tetrahedra that share corners with two equivalent KN4 tetrahedra, corners with two OsN4 tetrahedra, and an edgeedge with one KN6 pentagonal pyramid. There is two shorter (1.82 Å) and two longer (1.87 Å) Os–N bond length. In the seventh Os6+ site, Os6+ is bonded to four N3- atoms to form OsN4 tetrahedra that share a cornercorner with one KN6 pentagonal pyramid, a cornercorner with one KN4 tetrahedra, corners with two OsN4 tetrahedra, and an edgeedge with one KN6 pentagonal pyramid. There are a spread of Os–N bond distances ranging from 1.81–1.88 Å. There are nineteen inequivalent N3- sites. In the first N3- site, N3- is bonded in a 6-coordinate geometry to five K1+ and one Os6+ atom. In the second N3- site, N3- is bonded in a 2-coordinate geometry to three K1+ and two Os6+ atoms. In the third N3- site, N3- is bonded in a 6-coordinate geometry to five K1+ and one Os6+ atom. In the fourth N3- site, N3- is bonded in a 4-coordinate geometry to three K1+ and two Os6+ atoms. In the fifth N3- site, N3- is bonded in a 3-coordinate geometry to three K1+ and two Os6+ atoms. In the sixth N3- site, N3- is bonded in a 1-coordinate geometry to five K1+ and one Os6+ atom. In the seventh N3- site, N3- is bonded in a 6-coordinate geometry to five K1+ and one Os6+ atom. In the eighth N3- site, N3- is bonded in a 2-coordinate geometry to two K1+ and two Os6+ atoms. In the ninth N3- site, N3- is bonded in a 1-coordinate geometry to six K1+ and one Os6+ atom. In the tenth N3- site, N3- is bonded in a distorted octahedral geometry to five K1+ and one Os6+ atom. In the eleventh N3- site, N3- is bonded in a 2-coordinate geometry to four K1+ and two Os6+ atoms. In the twelfth N3- site, N3- is bonded in a 4-coordinate geometry to four K1+ and one Os6+ atom. In the thirteenth N3- site, N3- is bonded in a 3-coordinate geometry to four K1+ and two Os6+ atoms. In the fourteenth N3- site, N3- is bonded in a 5-coordinate geometry to four K1+ and two Os6+ atoms. In the fifteenth N3- site, N3- is bonded in a 1-coordinate geometry to five K1+ and one Os6+ atom. In the sixteenth N3- site, N3- is bonded in a 5-coordinate geometry to three K1+ and two Os6+ atoms. In the seventeenth N3- site, N3- is bonded in a 2-coordinate geometry to three K1+ and two Os6+ atoms. In the eighteenth N3- site, N3- is bonded in a 6-coordinate geometry to five K1+ and one Os6+ atom. In the nineteenth N3- site, N3- is bonded in a 1-coordinate geometry to four K1+ and one Os6+ atom.

36 MATERIALS SCIENCE↗
NASA NTRSDate not supplied

Metal-silicate Partitioning of Re, Ru, Pt, Os, Ti, Nb, and Ta in Reduced Differentiated Planetary Bodies

Siderophile (iron-loving) elements are strongly fractionated during differentiation of planetary bodies into core and mantle [1]. Because the fractionation is controlled by the pressure, temperature, redox conditions, and composition, this group of elements can provide important constraints on the conditions of accretion and core formation in early solar system bodies (planetesimals) and planets (Earth, Mercury, Venus)[2]. At the reducing conditions thought to prevail in the early solar system, Si is known to alloy with FeNi metallic liquids (e.g., [3]) affecting the activity coefficients of siderophile elements in FeNi liquids and thus ultimately their detailed partitioning between metal and silicate melt. The effect of Si can be significant for some siderophile elements, as demonstrated previously by (e.g., [4]: Ni, Co; [5,6]: Ge, As, Sb, Pd, Pt, Au). The effect of Si has not yet been determined for several key groups of siderophile elements including the highly siderophile Re, Ru and Os, and the weakly siderophile Ta, Nb, and Ti. Here, we report new experiments designed to quantify the effect of Si on the partitioning of Re, Pt, Os, Ru, Ti, Ta and Nb between metal and silicate melts. The results will be used to evaluate metal/silicate equilibrium for Nb, Ta, Ti and Nb/Ta ratios in planetary mantles, mantle concentrations of Ru, Re, Pt, Os during accretion, the evolution of Re/Os, Pt/Os ratios in magma oceans, and the role of late veneer in establishing Re and Ru abundances in the terrestrial mantle.

core formation↗
DOE OSTI2024

Exploring the Links between Structural Distortions, Orbital Ordering, and Multipolar Magnetic Ordering in Double Perovskites Containing Re(VI) and Os(VII)

A combination of high-resolution powder diffraction techniques and solid-state NMR has been employed to explore the links between crystal structure, orbital ordering, and magnetism in three isostructural double perovskites containing transition metal ions with a 5d 1 configuration. In Ba 2 ZnReO 6 , both neutron and synchrotron X-ray powder diffraction data reveal a cubic-to-tetragonal transition at 23 K that breaks the degeneracy of the t 2g orbitals and leads to a pattern of orbital ordering that stabilizes magnetic ordering when the sample is cooled below 16 K. Similar behavior is observed in Ba 2 MgReO 6 , with an orbital ordering temperature of 33 K and a magnetic ordering temperature of 18 K. Prior theoretical works suggest that the pattern of orbital order seen in the P42/mnm space group is needed to stabilize the heavily canted antiferromagnetism of these compounds. Unfortunately, powder diffraction data is not sensitive enough to differentiate between the I4/mmm and P42/mnm structural models, as the distortions are too subtle to be unambiguously identified from either neutron or synchrotron X-ray powder diffraction methods. In contrast, both diffraction and 7 Li NMR data indicate that Ba 2 LiOsO 6 retains the cubic structure down to 1.7 K. The antiferromagnetic ground state and lack of any sign of orbital ordering in Ba 2 LiOsO 6 provide compelling evidence that the electronically driven tetragonal distortion seen in Ba2ZnReO6, and Ba2MgReO6 is intimately linked to the magnetic ordering seen in those compounds. The absence of magnetic reflections in high intensity neutron powder diffraction data collected on Ba 2 MgReO 6 strongly suggests ordering of multipolar moments on Re(VI), likely ferro-octupolar ordering.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2003

Project Status Update and SIM Science Breadth Discussion for the Origins Subcommittee (OS)

This viewgraph presentation is composed of two sections The first reviews the features and the science goals of the Space Interferometry Mission (SIM). The goals are: (1) Perform a search for other planetary systems by surveying 2000 nearby stars for astrometric signatures of planetary companion, (2) Survey a sample of 200 nearby stars for orbiting planets down to terrestrial-type masses (3) Improve best current catalog of star positions by >lOOx and extend to fainter stars to allow extension of stellar knowledge to include our entire galaxy (4) Study dynamics and evolution of stars and star clusters in our galaxy to understand how our galaxy was formed and how it will evolve. (5) Calibrate luminosities of important stars and cosmological distance indicators to improve our understanding of stellar processes and to measure precise distance in the distant universe. The presentation also reviews the accomplishments since 2002, the plans for the subsequent 6 months. The second entitled "The Breadth of SIM Science," reviews SIM science goals in a larger context. SIM will serve to complement and pave the way for the Terrestrial Planet Finder (TPF). SIM observations of the motions of stars will tell us about the distribution of all gravitating mass (light plus dark matter) in the Galaxy. SIM observations of the motions of dwarf galaxies around our own will determine the mass distribution (light plus dark matter in the Halo. SIM will greatly extend these observations to test the theories of accretion disks around super massive black holes. SIM has advantages for studying AGN and other very compact objects.

Michelson stellar interferometers↗
DOE OSTI2025

Performance of the spin-component-scaled methods for energy bands

The performance of various spin-component-scaled parameterisations is examined for the second-order many-body Green's-function [MBGF(2)] calculations of valence energy bands, taking three of the experimentally well-characterised polymers as examples: polyethylene, polytetrafluoroethylene, and polyacetylene. The parameterisations considered are Grimme's original SCS parameter set, Jung et al.'s original SOS set (retaining the opposite-spin component only), Śmiga et al.'s SCS(IP) set (calibrated specifically for ionization energies), and Śmiga et al.'s SOS(IP) set (calibrated for ionization energies with the opposite-spin component only; implicit in the os-D2 model of Opoku et al.). The SCS(IP) and SOS(IP) parameterisations are found to shift both outer and inner valence bands by up to a few electronvolts away from the experimental data. The original SCS and SOS parameter sets do not improve upon, but largely maintain the accuracy of the unscaled MBGF(2) methods. Given that the SOS-MBGF(2) method can be implemented in a quartic-scaling algorithm (for all roots), it is most promising for solid-state applications. Furthermore this observation is consistent with the success of the quartic-scaling GW methods without the vertex correction based on a density-functional theory reference.

Green’s-function theory↗
DOE OSTI2020

Synthesis, Crystal Structure, and Cooperative 3d–5d Magnetism in Rock Salt Type Li 4 NiOsO 6 and Li 3 Ni 2 OsO 6

Two new transition metal oxides with the nominal chemical compositions of Li 4 NiOsO 6 and Li 3 Ni 2 OsO 6 were successfully synthesized. Both compounds crystallize in an ordered rock salt structure type in the monoclinic C2/m space group. The crystal structures were determined using both synchrotron X-ray and time-of-flight neutron, powder diffraction data. In both phases, Ni2+ ions are present while oxidation states of osmium are +6 and +5 in Li 4 NiOsO 6 and Li 3 Ni 2 OsO 6 , respectively. Ni2+ ions in the hypothetical fully ordered phase form a honeycomb arrangement in the ab crystallographic plane and these hexagons are centered by osmium ions. Furthermore, the magnetic layers are separated along the c axis by the octahedra, which are centered by Li+ (or Li+/Ni 2+ , depending on the chemical compositions). Crystal structure refinements reveal that there is some degree of mixed occupancy in cationic positions. Temperature dependent magnetic susceptibility data for both phases show ferrimagnetic transitions with predominant antiferromagnetic (AFM) interactions among 3d electrons of nickel and Sd electrons of osmium. Iso-thermal magnetization loops as a function of the applied magnetic field below the transition temperatures confirm the ferrimagnetic nature in magnetic transitions. Temperature dependent heat capacity data, however, did not exhibit any anomaly in either phase, indicating the absence of long-range magnetic ordering. The lack of long-range order for both Os 5+ and Os 6+ -based compounds was also confirmed by low temperature neutron diffraction data down to 10 K. Temperature dependent AC magnetic susceptibility data in various frequencies for both samples indicate that Li 4 NiOsO 6 exhibits spin-glass-like behavior, while the transition temperature for Li 3 Ni 2 OsO 6 is nearly frequency independent.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2006

History of Metal Veins in Acapulcoite-Lodranite Clan Meteorite GRA 95209

Graves Nunataks (GRA) 95209 has been hailed as the missing link of core formation processes in the acapulcoitelodranite parent asteroid because of the presence of a complex cm-scale metal vein network. Because the apparent liquid temperature of the metal vein (approximately 1500 C) is higher than inferred for the metamorphic grade of the meteorite, questions regarding the vein s original composition, temperature, and mechanism of emplacement have arisen. We have determined trace siderophile element compositions of metals in veins and surrounding matrix in an effort to clarify matters. We analyzed metals in GRA 95209 in a portion of thick metal vein and adjacent metal-rich (30-40 modal%), sulfide poor (less than 1%) matrix by EPMA and LA-ICP-MS for major and trace siderophile elements using methods described by [3]. We also examined metals from a metal-poor (approximately 15 modal%) and relatively sulfide-rich (2-5 modal%) region of the sample. Kamacite is the dominant metal phase in all portions of the sample. In comparison to matrix metal, vein metal contains more schreibersite and less tetrataenite, and is less commonly associated with Fe,Mn,Mg-bearing phosphates and graphite. Vein kamacite contains higher Co, P, and Cr and lower Cu and Ge. These minor variations aside, all metal types in GRA 95209 are fairly homogeneous in terms of their levels of enrichment of compatible siderophile elements (e.g. Pt, Ir, Os) relative to incompatible siderophile elements (e.g. As, Pd, Au), consistent with the loss of metal-sulfide partial melt that characterizes much of the clan. Whatever compositional differences between matrix and vein metal that may have originally existed, they have since largely co-equilibrated to similar restitic trace element compositions. We agree with [2] that metal veins, in their present state, do not represent a liquid composition. The original vein liquid was much more S-rich and emplaced at correspondingly lower liquid temperatures. Much of the Fe,Ni component solidified in cm scale conduits while S-rich melts were expelled and continued to migrate by percolation. The higher troilite content in metal poor regions of the sample results mostly from trapping of a small portion of these melts. The troilite is not remnant primary sulfide. Strong depletions of W, Mo, and especially Ga (greater than 50%, greater than 60%, and greater than 90% depletion, respectively) in metals of the metalpoor GRA 95209 lithology are localized at scales of 10-100 micrometers in the vicinity of graphite spherules. These depletions must have occurred below the temperatures at which cm-scale equilibration occurred, and future work will seek to determine their cause.

Herrin, J. S.↗
NASA NTRS1990

Infrared spectroscopy of the dwarf starburst galaxy Henize 2-10

Researchers present 1.2 to 2.2 micron spectra of the nucleus of Henize 2 to 10, taken at United Kingdom Infrared Telescope (UKIRT) with the cool grating spectrometer 2 (CGS 2). This galaxy displays strong line emission from interstellar H (+) (1.282 and 2.166 microns) and (Fe (+)) (1.256 and 1.644 microns), in common with other star-forming galaxy nuclei. However, the 1 to 0 S(1) line of molecular hydrogen at 2.122 micron is not detected - the upper limit of 0.15 (3 sigma) for the value of the flux ratio I sub 1-os(1)/I sub Br gamma is much lower than the typical values of 0.4 to 0.9 measured in a sample of 28 non-interacting starburst galaxies. From the Pa beta/Br gamma line ratio researchers derive a total extinction of A sub v approx. 4 mag. The de-reddened H (+) and (Fe (+) line fluxes are used to estimate the total ionizing luminosity and the average supernova rate in the central 150 pc of He 2 to 10. By comparison of these estimates with existing Infrared Astronomy Satellite (IRAS) and radio continuum data, researchers are able to set limits on the range of stellar masses present in this unevolved (less than 10(exp 7) year old) starburst nucleus. Possible reasons for the low H2/H+ line ratios observed in young starburst systems (He 2 to 10, NGC 7714, IIZw40; e.g., Moorwood and Oliva 1988) are briefly discussed.

Blanco, P. R.↗
NASA NTRS1973

NASIS data base management system - IBM 360/370 OS MVT implementation. 6: NASIS message file

The message file for the NASA Aerospace Safety Information System (NASIS) is discussed. The message file contains all the message and term explanations for the system. The data contained in the file can be broken down into three separate sections: (1) global terms, (2) local terms, and (3) system messages. The various terms are defined and their use within the system is explained.

Source record↗
DOE OSTI2025

Breaking the Brønsted–Evans–Polanyi Relation with Dual-Metal Sites

Linear scaling relationships impose inherent limitations on catalyst activity; the Brønsted−Evans−Polanyi (BEP) relation, which correlates activation and reaction energies, is a prominent example. Here we report a dual-metal site catalyst (DMSC) on ceria that breaks the BEP relation for C−C coupling of methyl intermediates an elementary step in methane coupling to form ethane. The DMSC structure on CeO 2 (111) was discovered by density-functional theory (DFT) structural exploration and confirmed to be stable via ab initio thermodynamics and ab initio molecular dynamics. Homonuclear and heteronuclear DMSCs of Ni, Pd, Pt, Fe, Ru, Os, Co, Rh, and Ir (45 pairs in total) were examined for methyl affinity and methyl−methyl coupling activation energy. We found that many heteronuclear DMSCs break the BEP linear scaling due to a mixed low-affinity/high-affinity coadsorption of the two methyl groups, decoupling the step responsible for the activation energy (E a ) at the low-affinity site from the overall reaction energy (ΔE) determined by both sites. This mechanism of breaking the BEP relationship via the DMSCs offers a catalyst design principle for C−C coupling reactions.

Chen, Yiming [Vanderbilt Univ., Nashville, TN (Uni↗