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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on CeThB8 by Materials Project

ThCeB8 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. Th is bonded in a 8-coordinate geometry to eighteen B atoms. There are a spread of Th–B bond distances ranging from 2.77–3.07 Å. Ce is bonded in a 12-coordinate geometry to eighteen B atoms. There are a spread of Ce–B bond distances ranging from 2.75–3.09 Å. There are five inequivalent B sites. In the first B site, B is bonded in a 1-coordinate geometry to two equivalent Th, two equivalent Ce, and five B atoms. There are a spread of B–B bond distances ranging from 1.65–1.79 Å. In the second B site, B is bonded in a 9-coordinate geometry to two equivalent Th, two equivalent Ce, and five B atoms. There are a spread of B–B bond distances ranging from 1.74–1.84 Å. In the third B site, B is bonded in a 9-coordinate geometry to two equivalent Th, two equivalent Ce, and five B atoms. The B–B bond length is 1.74 Å. In the fourth B site, B is bonded in a distorted trigonal planar geometry to four equivalent Th, two equivalent Ce, and three B atoms. The B–B bond length is 1.82 Å. In the fifth B site, B is bonded in a distorted trigonal planar geometry to two equivalent Th, four equivalent Ce, and three B atoms. The B–B bond length is 1.81 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Synthesis of Parent Acetylide and Dicarbide Complexes of Thorium and Uranium and an Examination of Their Electronic Structures

The reaction of [AnCl(NR 2 ) 3 ] (An = U or Th; R = SiMe 3 ) with NaCCH and tetramethylethylenediamine (TMEDA) results in the formation of [An(C≡CH)(NR 2 ) 3 ] (1, An = U; 2, An = Th), which can be isolated in good yields after workup. Similarly, the reaction of 3 equiv of NaCCH and TMEDA with [AnCl(NR 2 ) 3 ] results in the formation of [Na(TMEDA)][An(C≡CH) 2 (NR 2 ) 3 ] (4, An = U; 5, An = Th), which can be isolated in fair yields after workup. The reaction of 1 with 2 equiv of KC 8 and 1 equiv of 2.2.2-cryptand in tetrahydrofuran results in formation of the uranium(III) acetylide complex [K(2.2.2-cryptand)][U(C≡CH)(NR 2 ) 3 ] (3). Thermolysis of 1 or 2 results in formation of the bimetallic dicarbide complexes [{An(NR 2 ) 3 } 2 (μ,η 1 :η 1 -C 2 )] (6, An = U; 7, An = Th), whereas the reaction of 1 with [Th{N(R)(SiMe 2 CH 2 )}(NR 2 ) 2 ] results in the formation of [U(NR 2 ) 3 (μ,η 1 :η 1 -C 2 )Th(NR 2 ) 3 ] (8). The 13 C NMR chemical shifts of the α-acetylide carbon atoms in 2, 5, and 7 exhibit a characteristic spin–orbit-induced downfield shift, due to participation of the 5f orbitals in the Th–C bonds. Furthermore, magnetism measurements demonstrate that 6 displays weak ferromagnetic coupling between the uranium(IV) centers (J = 1.78 cm –1 ).

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

ThAu 2 – , ThAu 2 O – , and ThAuOH – anions: Photoelectron spectroscopic and theoretical characterization

The thorium–gold negative ions ThAu 2 – , ThAu 2 O – , and ThAuOH – have been observed and experimentally characterized by anion photoelectron spectroscopy. These experiments are accompanied by extensive ab initio electronic structure calculations using a relativistic composite methodology based primarily on coupled cluster singles and doubles with perturbative triples calculations. The theoretical electron affinities (EAs) at 0 K agree with the experimental adiabatic EAs to within 0.02 eV for all species. Two separate isomers were located in the calculations for ThAuOH – , and detachment from both of these appears to be present in the photoelectron spectrum. Excited electronic states of the neutral molecules are reported at the equation of motion-coupled cluster singles and doubles level of theory. Atomization energies and heats of formation are also calculated for each neutral species and have expected uncertainties of 3 and 4 kcal/mol, respectively. The σ bonds between Th and Au are determined by natural bond orbital analysis to consist of predominately sd hybrids on Th bonding with the Au 6s orbital. In order to investigate the correspondence between the bonding in Th–Au and Th–F molecules, a limited number of calculations were also carried out on most of the F-analogs of this study. These results demonstrate that Au does behave like F in these cases, although the Th–F σ bonds are much more ionic compared to Th–Au. This results in an EA for ThF 2 that is 10 kcal/mol smaller than that of ThAu 2 . The EA values for the Th(IV) species, i.e., ThX 2 O and ThXOH, only differed, however, by 3–4 kcal/mol.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Thermal energy mitigation and toroidal peaking effects in JET disruptions

Previous investigations on JET suggest half or less of plasma stored thermal energy W th is radiated (f rad,th ≲ 0.5) using either massive gas injection (MGI) or shattered pellet injection (SPI) disruption mitigation. We investigate whether the apparent incomplete f rad,th is explained by radiation peaking near the injection plume. High toroidal peaking throughout the pre-thermal quench is found in argon–deuterium MGI on JET, with typically >3× higher radiation near the injector than toroidally distant. Previously unexplained toroidal bolometry measurements in neon–deuterium SPI are reproduced with similar peaking using the Emis3D radiation analysis code. These observations align with results from Alcator C-Mod and KSTAR. This peaking is not captured by previous JET studies that found poor thermal mitigation. Two sets of neon–deuterium SPI and two sets of argon–deuterium MGI are analyzed using Emis3D. In SPI, f rad,th rises from no-plume estimates of 0.31 and 0.66 to lower bounds of 0.84 and 0.92, respectively, and f rad,th ∼ 1 is possible. In MGI, the toroidal spread of the peaking feature is poorly constrained. f rad,th up to 0.85 and 0.65 are possible using the largest possible spread, increasing from 0.42 and 0.28, although f rad,th ∼ 1 does not appear to be reached. Revised mitigation estimates on JET suggest a lower melt risk to the divertor in mitigated disruptions on ITER and SPARC than previously thought. However, peaking near injectors could increase flash melting risk on nearby plasma facing components.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2020

Differential ultrastructural alterations in the Vglut2 glutamatergic input to the substantia nigra pars compacta/pars reticulata following nigrostriatal dopamine loss in a progressive mouse model of Parkinson’s disease

Abstract Loss of nigrostriatal dopamine (DA) in Parkinson's disease results in over‐activation/bursting of the subthalamic nucleus (STN). The STN projects to the substantia nigra (SN) pars compacta (SNpc) and pars reticulata (SNpr). The vesicular glutamate transporter 2 (Vglut2) is localized within at least STN terminals synapsing within the SN, but it is not known if there are differential changes in the Vglut2+ input to the SNpc versus SNpr following DA loss. The goal/rationale of this current study was to determine whether there were differential changes in the density/levels of glutamate immuno‐gold labeling within Vglut2+ nerve terminals synapsing in the SNpc/SNpr and in the proportion of Vglut2+ terminals contacting tyrosine hydroxylase (TH) positively(+) or negatively(−) labeled dendrites following DA loss. Within the SNpc, there was a significant increase (51.3%) in the density of nerve terminal glutamate immuno‐gold labeling within Vglut2+ terminals synapsing on TH(−) dendrites following MPTP versus the vehicle ( VEH ) group. There was a significant decrease (16%) in the percentage of Vglut2+ terminals contacting TH(+) labeled dendrites in the MPTP‐ versus VEH‐treated group within the SNpc. Within the SNpr, there was a significant decrease in the density of glutamate immuno‐gold labeling in Vglut2+ terminals contacting TH(+) (71.5%) and TH(−) (55.5%) labeled dendrites, suggesting an increase in glutamate release. There was no change in the percentage of Vglut2+ terminals contacting TH(+) or TH(−) dendrites in the SNpr. We conclude that there is a differential effect following DA loss on the glutamate input from Vglut2+ terminals synapsing within the SNpr versus SNpc.

Moore, Cynthia↗
DOE OSTI2020

Materials Data on ThCd2 by Materials Project

ThCd2 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Th is bonded in a 12-coordinate geometry to two equivalent Th and twelve equivalent Cd atoms. Both Th–Th bond lengths are 3.38 Å. All Th–Cd bond lengths are 3.42 Å. Cd is bonded in a 11-coordinate geometry to six equivalent Th and five equivalent Cd atoms. There are three shorter (2.97 Å) and two longer (3.38 Å) Cd–Cd bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ThAl2 by Materials Project

ThAl2 is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Th is bonded in a 12-coordinate geometry to four equivalent Th and twelve equivalent Al atoms. All Th–Th bond lengths are 3.49 Å. All Th–Al bond lengths are 3.34 Å. Al is bonded to six equivalent Th and six equivalent Al atoms to form a mixture of face, edge, and corner-sharing AlTh6Al6 cuboctahedra. All Al–Al bond lengths are 2.85 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ThCoSn by Materials Project

ThCoSn crystallizes in the hexagonal P-62m space group. The structure is three-dimensional. Th is bonded in a 11-coordinate geometry to five Co and six equivalent Sn atoms. There are four shorter (3.01 Å) and one longer (3.04 Å) Th–Co bond lengths. There are two shorter (3.21 Å) and four longer (3.35 Å) Th–Sn bond lengths. There are two inequivalent Co sites. In the first Co site, Co is bonded in a 9-coordinate geometry to six equivalent Th and three equivalent Sn atoms. All Co–Sn bond lengths are 2.82 Å. In the second Co site, Co is bonded in a 9-coordinate geometry to three equivalent Th and six equivalent Sn atoms. All Co–Sn bond lengths are 2.74 Å. Sn is bonded in a 12-coordinate geometry to six equivalent Th and four Co atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th6CoBr15 by Materials Project

Th6CoBr15 crystallizes in the cubic Im-3m space group. The structure is three-dimensional and consists of two Th6CoBr15 frameworks. Th is bonded to one Co and five Br atoms to form a mixture of edge and corner-sharing ThCoBr5 octahedra. The corner-sharing octahedral tilt angles are 0°. The Th–Co bond length is 2.79 Å. There are four shorter (2.93 Å) and one longer (3.09 Å) Th–Br bond lengths. Co is bonded in an octahedral geometry to six equivalent Th atoms. There are two inequivalent Br sites. In the first Br site, Br is bonded in an L-shaped geometry to two equivalent Th atoms. In the second Br site, Br is bonded in a linear geometry to two equivalent Th atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th2Zn17 by Materials Project

Th2Zn17 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Th is bonded in a 10-coordinate geometry to nineteen Zn atoms. There are a spread of Th–Zn bond distances ranging from 3.16–3.47 Å. There are four inequivalent Zn sites. In the first Zn site, Zn is bonded to two equivalent Th and ten Zn atoms to form a mixture of distorted face, edge, and corner-sharing ZnTh2Zn10 cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.60–2.77 Å. In the second Zn site, Zn is bonded to two equivalent Th and ten Zn atoms to form a mixture of distorted face, edge, and corner-sharing ZnTh2Zn10 cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.66–2.97 Å. In the third Zn site, Zn is bonded to three equivalent Th and nine Zn atoms to form a mixture of distorted face, edge, and corner-sharing ZnTh3Zn9 cuboctahedra. There are two shorter (2.59 Å) and one longer (2.89 Å) Zn–Zn bond lengths. In the fourth Zn site, Zn is bonded in a 2-coordinate geometry to one Th and thirteen Zn atoms. The Zn–Zn bond length is 2.61 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th2Cu by Materials Project

CuTh2 crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Th is bonded in a distorted q6 geometry to five equivalent Th and six equivalent Cu atoms. There are three shorter (3.10 Å) and two longer (3.12 Å) Th–Th bond lengths. All Th–Cu bond lengths are 3.47 Å. Cu is bonded in a 12-coordinate geometry to twelve equivalent Th and two equivalent Cu atoms. Both Cu–Cu bond lengths are 3.12 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th6FeBr15 by Materials Project

Th6FeBr15 crystallizes in the cubic Im-3m space group. The structure is three-dimensional and consists of two Th6FeBr15 frameworks. Th is bonded to one Fe and five Br atoms to form a mixture of edge and corner-sharing ThFeBr5 octahedra. The corner-sharing octahedral tilt angles are 0°. The Th–Fe bond length is 2.77 Å. There are four shorter (2.94 Å) and one longer (3.05 Å) Th–Br bond lengths. Fe is bonded in an octahedral geometry to six equivalent Th atoms. There are two inequivalent Br sites. In the first Br site, Br is bonded in a linear geometry to two equivalent Th atoms. In the second Br site, Br is bonded in an L-shaped geometry to two equivalent Th atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ThMg2 by Materials Project

ThMg2 is Cubic Laves structured and crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Mg is bonded to six equivalent Mg and six equivalent Th atoms to form a mixture of corner, edge, and face-sharing MgTh6Mg6 cuboctahedra. All Mg–Mg bond lengths are 3.02 Å. All Mg–Th bond lengths are 3.55 Å. Th is bonded in a 12-coordinate geometry to twelve equivalent Mg and four equivalent Th atoms. All Th–Th bond lengths are 3.70 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th2Fe17 by Materials Project

Th2Fe17 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Th is bonded in a 10-coordinate geometry to nineteen Fe atoms. There are a spread of Th–Fe bond distances ranging from 3.04–3.29 Å. There are four inequivalent Fe sites. In the first Fe site, Fe is bonded to two equivalent Th and ten Fe atoms to form a mixture of edge, corner, and face-sharing FeTh2Fe10 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.45–2.62 Å. In the second Fe site, Fe is bonded to two equivalent Th and ten Fe atoms to form a mixture of distorted edge, corner, and face-sharing FeTh2Fe10 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.47–2.75 Å. In the third Fe site, Fe is bonded to three equivalent Th and nine Fe atoms to form a mixture of edge, corner, and face-sharing FeTh3Fe9 cuboctahedra. There are two shorter (2.48 Å) and one longer (2.65 Å) Fe–Fe bond lengths. In the fourth Fe site, Fe is bonded in a 2-coordinate geometry to one Th and thirteen Fe atoms. The Fe–Fe bond length is 2.40 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YbTh3 by Materials Project

Th3Yb is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Th is bonded to eight equivalent Th and four equivalent Yb atoms to form ThYb4Th8 cuboctahedra that share corners with twelve equivalent ThYb4Th8 cuboctahedra, edges with eight equivalent YbTh12 cuboctahedra, edges with sixteen equivalent ThYb4Th8 cuboctahedra, faces with four equivalent YbTh12 cuboctahedra, and faces with fourteen equivalent ThYb4Th8 cuboctahedra. All Th–Th bond lengths are 3.58 Å. All Th–Yb bond lengths are 3.58 Å. Yb is bonded to twelve equivalent Th atoms to form YbTh12 cuboctahedra that share corners with twelve equivalent YbTh12 cuboctahedra, edges with twenty-four equivalent ThYb4Th8 cuboctahedra, faces with six equivalent YbTh12 cuboctahedra, and faces with twelve equivalent ThYb4Th8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LuTh3 by Materials Project

Th3Lu is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Th is bonded to eight equivalent Th and four equivalent Lu atoms to form ThLu4Th8 cuboctahedra that share corners with twelve equivalent ThLu4Th8 cuboctahedra, edges with eight equivalent LuTh12 cuboctahedra, edges with sixteen equivalent ThLu4Th8 cuboctahedra, faces with four equivalent LuTh12 cuboctahedra, and faces with fourteen equivalent ThLu4Th8 cuboctahedra. All Th–Th bond lengths are 3.56 Å. All Th–Lu bond lengths are 3.56 Å. Lu is bonded to twelve equivalent Th atoms to form LuTh12 cuboctahedra that share corners with twelve equivalent LuTh12 cuboctahedra, edges with twenty-four equivalent ThLu4Th8 cuboctahedra, faces with six equivalent LuTh12 cuboctahedra, and faces with twelve equivalent ThLu4Th8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SmTh3 by Materials Project

Th3Sm is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Th is bonded to eight equivalent Th and four equivalent Sm atoms to form ThSm4Th8 cuboctahedra that share corners with twelve equivalent ThSm4Th8 cuboctahedra, edges with eight equivalent SmTh12 cuboctahedra, edges with sixteen equivalent ThSm4Th8 cuboctahedra, faces with four equivalent SmTh12 cuboctahedra, and faces with fourteen equivalent ThSm4Th8 cuboctahedra. All Th–Th bond lengths are 3.57 Å. All Th–Sm bond lengths are 3.57 Å. Sm is bonded to twelve equivalent Th atoms to form SmTh12 cuboctahedra that share corners with twelve equivalent SmTh12 cuboctahedra, edges with twenty-four equivalent ThSm4Th8 cuboctahedra, faces with six equivalent SmTh12 cuboctahedra, and faces with twelve equivalent ThSm4Th8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th3Mg by Materials Project

MgTh3 is Uranium Silicide structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Mg is bonded to twelve equivalent Th atoms to form MgTh12 cuboctahedra that share corners with twelve equivalent MgTh12 cuboctahedra, edges with twenty-four equivalent ThTh8Mg4 cuboctahedra, faces with six equivalent MgTh12 cuboctahedra, and faces with twelve equivalent ThTh8Mg4 cuboctahedra. All Mg–Th bond lengths are 3.51 Å. Th is bonded to four equivalent Mg and eight equivalent Th atoms to form ThTh8Mg4 cuboctahedra that share corners with twelve equivalent ThTh8Mg4 cuboctahedra, edges with eight equivalent MgTh12 cuboctahedra, edges with sixteen equivalent ThTh8Mg4 cuboctahedra, faces with four equivalent MgTh12 cuboctahedra, and faces with fourteen equivalent ThTh8Mg4 cuboctahedra. All Th–Th bond lengths are 3.51 Å.

36 MATERIALS SCIENCE↗