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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Tl(NiS)2 by Materials Project

TlNi2S2 is alpha bismuth trifluoride-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ni+1.50+ is bonded to four equivalent S2- atoms to form a mixture of edge and corner-sharing NiS4 tetrahedra. All Ni–S bond lengths are 2.25 Å. Tl1+ is bonded in a body-centered cubic geometry to eight equivalent S2- atoms. All Tl–S bond lengths are 3.33 Å. S2- is bonded in a 4-coordinate geometry to four equivalent Ni+1.50+ and four equivalent Tl1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(CuTe)2 by Materials Project

Cu2TlTe2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cu+1.50+ is bonded to four equivalent Te2- atoms to form a mixture of corner and edge-sharing CuTe4 tetrahedra. All Cu–Te bond lengths are 2.64 Å. Tl1+ is bonded in a body-centered cubic geometry to eight equivalent Te2- atoms. All Tl–Te bond lengths are 3.58 Å. Te2- is bonded in a 8-coordinate geometry to four equivalent Cu+1.50+ and four equivalent Tl1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(CuS)2 by Materials Project

TlCu2S2 is alpha bismuth trifluoride-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Cu+1.50+ is bonded to four equivalent S2- atoms to form a mixture of corner and edge-sharing CuS4 tetrahedra. All Cu–S bond lengths are 2.35 Å. Tl1+ is bonded in a body-centered cubic geometry to eight equivalent S2- atoms. All Tl–S bond lengths are 3.35 Å. S2- is bonded in a 4-coordinate geometry to four equivalent Cu+1.50+ and four equivalent Tl1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(V3S4)2 by Materials Project

TlV6S8 crystallizes in the trigonal P-3 space group. The structure is three-dimensional. V+2.50+ is bonded to six S2- atoms to form a mixture of edge, corner, and face-sharing VS6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of V–S bond distances ranging from 2.32–2.58 Å. Tl1+ is bonded in a 6-coordinate geometry to six equivalent S2- atoms. All Tl–S bond lengths are 3.12 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a 5-coordinate geometry to four equivalent V+2.50+ and one Tl1+ atom. In the second S2- site, S2- is bonded to six equivalent V+2.50+ atoms to form distorted face-sharing SV6 pentagonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Exploring the Tl 2H 2 potential energy surface: A comparative analysis with group 13 systems and experiment

Abstract Thallium chemistry is experiencing unprecedented importance. Therefore, it is valuable to characterize some of the simplest thallium compounds. Stationary points along the singlet and triplet TlH potential energy surface have been characterized. Stationary point geometries were optimized with the CCSD(T)/aug‐cc‐pwCVQZ‐PP method. Harmonic vibrational frequencies were computed at the same level of theory while anharmonic vibrational frequencies were computed at the CCSD(T)/aug‐cc‐pwCVTZ‐PP level of theory. Final energetics were obtained with the CCSDT(Q) method. Basis sets up to augmented quintuple‐zeta cardinality (aug‐cc‐pwCV5Z‐PP) were employed to obtain energetics in order to extrapolate to the complete basis set limits using the focal point approach. Zero‐point vibrational energy corrections were appended to the extrapolated energies in order to determine relative energies at 0 K. It was found that the planar dibridged isomer lies lowest in energy while the linear structure lies highest in energy. The results were compared to other group 13 MH (M = B, Al, Ga, In, and Tl) theoretical studies and some interesting variations are found. With respect to experiment, incompatibilities exist.

Chemistry↗
DOE OSTI2021

CeNTREX: a new search for time-reversal symmetry violation in the 205 Tl nucleus

The Cold molecule Nuclear Time-Reversal EXperiment (CeNTREX) is a new effort aiming for a significant increase in sensitivity over the best present upper bounds on the strength of hadronic time reversal (T) violating fundamental interactions. The experimental signature will be shifts in nuclear magnetic resonance frequencies of 205 Tl in electrically-polarized thallium fluoride (TlF) molecules. Here we describe the motivation for studying these T-violating interactions and for using TlF to do so. To achieve higher sensitivity than earlier searches for T-violation in TlF, CeNTREX uses a cryogenic molecular beam source, optical state preparation and detection, and modern methods of coherent quantum state manipulation. Details of the measurement scheme and the current state of the apparatus are presented, with quantitative measurements of the TlF beam. Lastly, the estimated sensitivity and methods to control systematic errors are discussed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Nonperturbative phonon scatterings and the two-channel thermal transport in Tl 3 VSe 4

We review the role of nonperturbative phonon scattering in strongly anharmonic materials having ultralow lattice thermal conductivity with unusual temperature dependence. We take Tl 3 VSe 4 as an example and investigate its lattice dynamics using perturbation theory (PT) up to the fourth order and molecular dynamics (MD) with a machine-learning potential. We find distinct differences of phonon linewidth between PT and MD in the whole Brillouin zone. The comparison between the theoretical phonon linewidths and experiments suggests that PT severely underestimates the phonon scatterings, even when the fourth-order anharmonicity is included. Moreover, we extend our calculations to higher temperatures and evaluate the two-channel thermal conductivity based on the unified theory developed by Simoncelli et al. [Nat. Phys. 15, 809 (2019)]. We find a crucial coherence contribution to the total thermal conductivity at high temperatures. Our results pave the path for future studies of phonon properties and lattice thermal conductivities of strongly anharmonic crystals beyond the conventional PT realm.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2020

Thermal Characterization of Tl 2 LiYCl 6 :Ce (TLYC)

Tl 2 LiYCl 6 :Ce (TLYC) is a new dual-detection elpasolite scintillator that can detect and distinguish between gamma rays and neutrons using pulse shape discrimination (PSD). It has a higher density and Z -number than the more mature and well-known elpasolite Cs 2 LiYCl 6 :Ce (CLYC), causing it to have a significantly better gamma-ray stopping power. These properties make TLYC an attractive alternative to CLYC for resource-constrained applications where size and weight are important, such as space or national security applications. Such applications may be subjected to a wide range of temperatures, and therefore, TLYC's performance was characterized for the first time over a temperature range of -20 °C to +50 °C in 10 °C increments. TLYC's thermal response effects on light-output linearity with energy, gamma-ray photopeak energy resolution, detected neutron energy, pulse shapes, and figure of merit (FOM) is analyzed and reported. The light output of TLYC was found to be linear with energy over the tested temperature range and was observed to decrease with increasing temperature. The decay time of the scintillation light output was observed to decrease with decreasing temperature at short times, leading to a decreasing PSD FOM. The gamma-ray photopeak energy resolution was also observed to degrade with decreasing temperature, due to an asymmetric broadening of the photopeak at low temperatures.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Characterizing the energy resolution of the MicroBooNE LArTPC at the MeV scale using monoenergetic features of $^{208}$Tl decays

A detailed understanding of the capabilities and fidelity of low-energy reconstruction is crucial for taking advantage of MeV-scale neutrino physics opportunities in liquid argon time projection chambers (LArTPCs). This study presents a measurement of the resolution of reconstructed energy in the MicroBooNE LArTPC at $\approx 1.5$ MeV. The characterization is performed using monoenergetic signals generated by $2.614$ MeV $γ$-rays from $^{208}$Tl decays undergoing pair production in the detector. The resolution is found to be ($7.52 \pm 0.78 \text{(stat)} \pm 0.92 \text{(syst)}$)%. This value is consistent with the MicroBooNE simulation prediction of ($9.70 \pm 0.65 \text{(stat)}$)% at the $1.6 σ$ level. This study represents the first ever measurement of LArTPC energy resolution at the MeV scale and provides a pathway for monoenergetic energy calibrations in future experiments using LArTPC detectors.

Abratenko, P. [Tufts U.]↗
DOE OSTI2020

Materials Data on Tl(TeMo)3 by Materials Project

(MoTe)3Tl crystallizes in the hexagonal P6_3/m space group. The structure is one-dimensional and consists of two thallium molecules and one MoTe ribbon oriented in the (0, 0, 1) direction. In the MoTe ribbon, Mo is bonded in a 10-coordinate geometry to six equivalent Mo and four equivalent Te atoms. There are two shorter (2.67 Å) and four longer (2.78 Å) Mo–Mo bond lengths. There are two shorter (2.84 Å) and two longer (2.89 Å) Mo–Te bond lengths. Te is bonded in a 4-coordinate geometry to four equivalent Mo atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(MoSe)3 by Materials Project

(MoSe)3Tl crystallizes in the hexagonal P6_3/m space group. The structure is one-dimensional and consists of two ramor molecules and one MoSe ribbon oriented in the (0, 0, 1) direction. In the MoSe ribbon, Mo is bonded in a distorted see-saw-like geometry to six equivalent Mo and four equivalent Se atoms. There are two shorter (2.67 Å) and four longer (2.74 Å) Mo–Mo bond lengths. There are a spread of Mo–Se bond distances ranging from 2.63–2.72 Å. Se is bonded in a 4-coordinate geometry to four equivalent Mo atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(MoO3)3 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl(WO3)3 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2022

Dose conversion factors for absorbed dose in a mobile phone to absorbed dose in critical organs in an anthropomorphic phantom for emergency dosimetry applications: OSL and TL experimental results, and Monte Carlo simulations

Here, an anthropomorphic phantom was equipped with three smartphones and irradiated in five separate exposure geometries in air using a 137 Cs source. The phantom was fitted internally with thermoluminescence dosimeters (TLD-700 chips) to measure the absorbed dose to the individual organs, while the absorbed doses in the phones were evaluated using optically stimulated luminescence (OSL) from the phones’ surface mount resistors (SMRs), along with reference dosimeters, namely Luxel OSL films and TLD-700 chips. The results indicate a strong dependence on the phone location with respect to the source due to shielding and scattering from the body. Dose conversion factors were calculated for several plausible exposure scenarios in order to correlate the absorbed doses measured in the phones to the average body dose received by the phantom. The measured conversion factors were compared with calculated factors using MCNP6.2 Monte Carlo simulations and an ADAM voxel phantom. Experiments were conducted to assess how the phone orientation and angle impacts the dose received by the phone components. The overall results indicate that the doses measured can vary significantly depending upon exposure geometry (including phone position and angle). However, in rotational irradiation symmetry, the phone doses lead to an over-estimate of the average whole-body dose by an average of ~10%, independent of the phone locations tested in this study. This result, if confirmed in future studies, may be acceptable for triage.

61 RADIATION PROTECTION AND DOSIMETRY↗