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At least 181 records · Page 10
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Tm(SiNi)2 by Materials Project

Tm(NiSi)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Tm3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Tm–Si bond lengths are 3.03 Å. Ni+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of corner and edge-sharing NiSi4 tetrahedra. All Ni–Si bond lengths are 2.29 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Tm3+, four equivalent Ni+2.50+, and one Si4- atom. The Si–Si bond length is 2.38 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(NiP)2 by Materials Project

Tm(NiP)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Tm3+ is bonded in a distorted body-centered cubic geometry to eight equivalent P3- atoms. All Tm–P bond lengths are 2.95 Å. Ni+1.50+ is bonded to four equivalent P3- atoms to form a mixture of edge and corner-sharing NiP4 tetrahedra. All Ni–P bond lengths are 2.26 Å. P3- is bonded in a 9-coordinate geometry to four equivalent Tm3+, four equivalent Ni+1.50+, and one P3- atom. The P–P bond length is 2.27 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(SiOs)2 by Materials Project

Tm(OsSi)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Tm3+ is bonded to eight equivalent Os+1.50- atoms to form distorted edge-sharing TmOs8 hexagonal bipyramids. All Tm–Os bond lengths are 3.17 Å. Os+1.50- is bonded in a 4-coordinate geometry to four equivalent Tm3+ and four equivalent Si atoms. All Os–Si bond lengths are 2.39 Å. Si is bonded in a 5-coordinate geometry to four equivalent Os+1.50- and one Si atom. The Si–Si bond length is 2.44 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(HO)3 by Materials Project

Tm(HO)3 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Tm3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Tm–O bond distances ranging from 2.36–2.67 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 0.98 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to three equivalent Tm3+ and one H1+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to three equivalent Tm3+ and one H1+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to three equivalent Tm3+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(HO)3 by Materials Project

Tm(HO)3 crystallizes in the hexagonal P6_3/m space group. The structure is three-dimensional. Tm3+ is bonded in a 9-coordinate geometry to nine equivalent O2- atoms. There are six shorter (2.37 Å) and three longer (2.47 Å) Tm–O bond lengths. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.97 Å. O2- is bonded in a single-bond geometry to three equivalent Tm3+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(CuO2)2 by Materials Project

Tm(CuO2)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Tm3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are six shorter (2.35 Å) and two longer (2.37 Å) Tm–O bond lengths. There are two inequivalent Cu+2.50+ sites. In the first Cu+2.50+ site, Cu+2.50+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.88 Å) and two longer (1.89 Å) Cu–O bond length. In the second Cu+2.50+ site, Cu+2.50+ is bonded in a square co-planar geometry to four O2- atoms. There is two shorter (1.91 Å) and two longer (1.93 Å) Cu–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Tm3+ and two Cu+2.50+ atoms to form a mixture of distorted corner and edge-sharing OTm2Cu2 tetrahedra. In the second O2- site, O2- is bonded to two equivalent Tm3+ and two Cu+2.50+ atoms to form a mixture of distorted corner and edge-sharing OTm2Cu2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(AlC)3 by Materials Project

Tm(AlC)3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Tm3+ is bonded to six equivalent C4- atoms to form TmC6 octahedra that share corners with six equivalent AlC4 tetrahedra, edges with six equivalent TmC6 octahedra, and edges with six equivalent AlC4 tetrahedra. All Tm–C bond lengths are 2.52 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four C4- atoms to form AlC4 tetrahedra that share corners with three equivalent TmC6 octahedra, corners with seven equivalent AlC4 tetrahedra, and edges with three equivalent TmC6 octahedra. The corner-sharing octahedral tilt angles are 19°. There are one shorter (2.02 Å) and three longer (2.10 Å) Al–C bond lengths. In the second Al3+ site, Al3+ is bonded in a trigonal planar geometry to three equivalent C4- atoms. All Al–C bond lengths are 1.97 Å. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to three equivalent Tm3+ and three equivalent Al3+ atoms to form distorted CTm3Al3 octahedra that share corners with three equivalent CTm3Al3 octahedra, corners with three equivalent CAl5 trigonal bipyramids, and edges with nine equivalent CTm3Al3 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second C4- site, C4- is bonded to five Al3+ atoms to form CAl5 trigonal bipyramids that share corners with six equivalent CTm3Al3 octahedra and corners with six equivalent CAl5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 70°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(Co2B)6 by Materials Project

Tm(Co2B)6 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Tm3+ is bonded in a hexagonal planar geometry to six equivalent B3- atoms. All Tm–B bond lengths are 3.03 Å. There are two inequivalent Co+1.25+ sites. In the first Co+1.25+ site, Co+1.25+ is bonded in a T-shaped geometry to three equivalent B3- atoms. All Co–B bond lengths are 2.10 Å. In the second Co+1.25+ site, Co+1.25+ is bonded to four equivalent B3- atoms to form a mixture of distorted edge and corner-sharing CoB4 trigonal pyramids. There are two shorter (2.02 Å) and two longer (2.04 Å) Co–B bond lengths. B3- is bonded in a 7-coordinate geometry to one Tm3+ and seven Co+1.25+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(CuS)3 by Materials Project

Tm(CuS)3 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Tm3+ is bonded to six equivalent S2- atoms to form TmS6 octahedra that share corners with twelve equivalent CuS4 tetrahedra, edges with three equivalent TmS6 octahedra, and edges with six equivalent CuS4 tetrahedra. There are three shorter (2.70 Å) and three longer (2.71 Å) Tm–S bond lengths. Cu1+ is bonded to four equivalent S2- atoms to form CuS4 tetrahedra that share corners with four equivalent TmS6 octahedra, corners with six equivalent CuS4 tetrahedra, edges with two equivalent TmS6 octahedra, and edges with three equivalent CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 16–55°. There are a spread of Cu–S bond distances ranging from 2.33–2.41 Å. S2- is bonded to two equivalent Tm3+ and four equivalent Cu1+ atoms to form a mixture of distorted edge and corner-sharing STm2Cu4 octahedra. The corner-sharing octahedra tilt angles range from 0–90°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(BRu)4 by Materials Project

Tm(RuB)4 crystallizes in the tetragonal I4_1/acd space group. The structure is three-dimensional. Tm3+ is bonded in a 12-coordinate geometry to twelve equivalent B3- atoms. There are a spread of Tm–B bond distances ranging from 2.96–3.21 Å. Ru+2.25+ is bonded to five equivalent B3- atoms to form a mixture of distorted edge and corner-sharing RuB5 trigonal bipyramids. There are a spread of Ru–B bond distances ranging from 2.15–2.28 Å. B3- is bonded in a 6-coordinate geometry to three equivalent Tm3+, five equivalent Ru+2.25+, and one B3- atom. The B–B bond length is 1.79 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(Mo3Se4)2 by Materials Project

Tm(Mo3Se4)2 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Tm3+ is bonded in a body-centered cubic geometry to eight Se2- atoms. There are two shorter (2.78 Å) and six longer (3.08 Å) Tm–Se bond lengths. Mo+2.17+ is bonded to five Se2- atoms to form a mixture of edge and corner-sharing MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.54–2.74 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 1-coordinate geometry to one Tm3+ and three equivalent Mo+2.17+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to one Tm3+ and four equivalent Mo+2.17+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tm(IO3)3 by Materials Project

Tm(O3I)3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Tm3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Tm–O bond distances ranging from 2.23–2.56 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Tm3+ and one I5+ atom. The O–I bond length is 1.85 Å. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Tm3+ and one I5+ atom. The O–I bond length is 1.84 Å. In the third O2- site, O2- is bonded in a distorted single-bond geometry to one I5+ atom. The O–I bond length is 1.83 Å. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Tm3+ and one I5+ atom. The O–I bond length is 1.83 Å. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one Tm3+ and one I5+ atom. The O–I bond length is 1.83 Å. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Tm3+ and one I5+ atom. The O–I bond length is 1.82 Å. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Tm3+ and one I5+ atom. The O–I bond length is 1.84 Å. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Tm3+ and one I5+ atom. The O–I bond length is 1.83 Å. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to one Tm3+ and one I5+ atom. The O–I bond length is 1.82 Å. There are three inequivalent I5+ sites. In the first I5+ site, I5+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. In the second I5+ site, I5+ is bonded in a 3-coordinate geometry to three O2- atoms. In the third I5+ site, I5+ is bonded in a 3-coordinate geometry to three O2- atoms.

36 MATERIALS SCIENCE↗
NASA NTRS2006

Landsat TM and ETM+ Thermal Band Calibration

Landsat-5 Thematic Mapper (TM) has been imaging the Earth since March 1984 and Landsat-7 Enhanced Thematic Mapper Plus (ETM+) was added to the series of Landsat instruments in April 1999. The stability and calibration of the ETM+ has been monitored extensively since launch. Though not monitored for many years, TM now has a similar system in place to monitor stability and calibration. University teams have been evaluating the on-board calibration of the instruments through ground-based measurements since 1999. This paper considers the calibration efforts for the thermal band, Band 6, of both the Landsat-5 and Landsat-7 instruments.

Thematic Mapper (TM)↗
DOE OSTI2022

Structure and thermodynamics of calcium rare earth silicate oxyapatites, Ca 2 RE 8 (SiO 4 ) 6 O 2 (RE = Pr, Tb, Ho, Tm)

Calcium rare earth silicate oxyapatites, (Ca 2 RE 8 (SiO 4 ) 6 O 2 ), are of interest as components of glass-ceramic nuclear waste forms. To assess their long-term behavior in a geologic repository, it is essential to determine their structure and thermodynamic stability at relevant conditions. Here, in this work, we performed detailed structural and thermodynamic investigations on Ca 2 Pr 8 (SiO 4 ) 6 O 2 , Ca 2 Tb 8 (SiO 4 ) 6 O 2 , Ca 2 Ho 8 (SiO 4 ) 6 O 2 , and Ca 2 Tm 8 (SiO 4 ) 6 O 2 by high energy synchrotron powder X-ray diffraction combined with Rietveld analysis and high temperature oxide melt drop solution calorimetry. Enthalpies of formation from constituent oxides (ΔH f,ox ) were determined to be -765.1 ± 22.8 kJ/mol for Ca 2 Pr 8 (SiO 4 ) 6 O 2 ; -638.9 ± 20.5 kJ/mol for Ca 2 Tb 8 (SiO 4 ) 6 O 2 ; -643.3 ± 10.3 kJ/mol for Ca 2 Ho 8 (SiO 4 ) 6 O 2 ; and -403.2 ± 5.1 kJ/mol for Ca 2 Tm 8 (SiO 4 ) 6 O 2 . These thermodynamic parameters were used in assessing the thermochemical stability of these phases in the presence of water vapor from room temperature to 600 K, as encountered in the subsurface environments of a geological repository.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Resistivity and magnetoresistance properties of R 2 NiSi 3 (R = Gd, Dy, Ho, Er, Tm) compounds

The resistivity and magnetoresistance behaviour of the hexagonal intermetallic compounds R 2 NiSi 3 (R = Gd, Dy, Ho, Er, and Tm) are reported here. All the studied polycrystalline compounds exhibit metallic behavior along with additional magnetic anomalies at low temperatures. A well-defined resistivity minima is observed in Gd 2 NiSi 3 and Dy 2 Ni 0.87 Si 2.95 at a temperature much higher than their respective magnetic transition temperatures. The anomaly has been ascribed to the charge carrier localization caused by magnetic precursor effect. Magnetic field induced crossover from positive to negative magnetoresistance (MR) behavior associated with antiferromagnetic ground state is evidenced for Gd 2 NiSi 3 and Er 2 NiSi 3 in the low temperature region. Although Tm 2 Ni 0.93 Si 2.93 does not exhibit any long range magnetic order down to 2 K, a sudden drop in resistivity behavior is observed below ~10 K. Furthermore, presence of short range magnetic correlation observed in a wide temperature range, much beyond their respective magnetic ordering temperatures, has been argued to be responsible for achieving finite negative MR for all the compounds. Additionally, a subtle resemblance between the observed transport anomalies and the magnetic properties of these systems has been discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Enhanced long-term cyclability in Li-Rich layered oxides by electrochemically constructing a Li x TM 3-x O 4 -type spinel shell

The poor long-term cycling stability, including the fast capacity fade and the severe voltage decay, has become the main concern hindering the practical application of Li-rich layered oxides, a promising cathode for high- energy-density Li-ion battery. Herein, we design and electrochemically construct a ~10 nm-thick Li x TM 3-x O 4 - type (TM ¼Ni, Co, Mn, 0 3 O 4 -type spinel phase and the good Liþconductivity of LiMn 2 O 4 -type spinel phase. Systemic structural and electrochemical analysis demonstrate that, it slows down the activation rate of Li 2 MnO 3 component and efficiently alleviates the lattice O loss at high voltage (>4.5 V) and Mn dissolution, thereby suppressing the structural degradation from the layered phase to the spinel phase in the bulk, eventually significantly enhancing the long-term cycling stability. This study adds richness into the Mn-based spinel phase system and provides a new heterostructure design strategy to improve the electrochemical performance of Li-rich layered cathodes and beyond.

25 ENERGY STORAGE↗
DOE OSTI2025

Magnetic properties of Tm 3+ in layered triangular lattices

Rare-earth chalcogenides, ARCh 2 (A = alkali metal or monovalent ion; R = rare-earth elements; Ch = O, S, and Se), have been identified as promising candidates for exploring a variety of novel frustrated quantum magnetic phenomena. Tm-based series, ATmCh 2 , where Tm 3+ ions are arranged on various frustrated geometric lattices, provide a platform for investigating the competitions among spin–orbit coupling, crystal field effects, and magnetic exchange interactions in the context of geometric frustration. In this study, we present how the crystallographic structures of newly synthesized ATmSe 2 (A = Li and Na) influence their frustrated magnetic behaviors. Both NaTmSe 2 and LiTmSe 2 adopt a delafossite-type structure with a two-dimensional (2D) triangular lattice, but LiTmSe 2 has a much shorter c-axis parameter compared to this in NaTmSe 2 . Both heat capacity and magnetic susceptibility measurements confirm the absence of long-range magnetic order in either compound. However, magnetic measurements data reveals the differences in magnetic interactions: NaTmSe 2 exhibits features of low-dimensional magnetism, likely driven by its layered crystal structure, compared to LiTmSe 2 .

Crystal field theory↗
DOE OSTI2022

Fine structure in the odd-odd proton emitter Tm 144

Axial symmetry breaking in 144 Tm is probed by examining its proton emission fine structure. The ground-state spin and parity in 144 Tm and daughter 143 Er are assigned unambiguously based on the corroboration of our calculations with the present data. Here we establish the first microscopic description of fine structure in odd-odd proton emitters, which is capable of resolving ambiguities present in the assignments of transitions in such nuclei.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗