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At least 1,261 records · Page 70
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on La2CdPd2 by Materials Project

La2Pd2Cd crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. La is bonded in a 6-coordinate geometry to six equivalent Pd and four equivalent Cd atoms. There are two shorter (2.98 Å) and four longer (3.15 Å) La–Pd bond lengths. All La–Cd bond lengths are 3.53 Å. Pd is bonded in a 9-coordinate geometry to six equivalent La, one Pd, and two equivalent Cd atoms. The Pd–Pd bond length is 2.80 Å. Both Pd–Cd bond lengths are 3.12 Å. Cd is bonded to eight equivalent La and four equivalent Pd atoms to form a mixture of corner and face-sharing CdLa8Pd4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd2PtAu by Materials Project

PtAuCd2 crystallizes in the orthorhombic Immm space group. The structure is one-dimensional and consists of two PtAuCd2 ribbons oriented in the (1, 0, 0) direction. Pt is bonded in a linear geometry to two equivalent Cd atoms. Both Pt–Cd bond lengths are 2.59 Å. Au is bonded in a linear geometry to two equivalent Cd atoms. Both Au–Cd bond lengths are 2.66 Å. Cd is bonded in a linear geometry to one Pt and one Au atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(CdGe)2 by Materials Project

Ba(CdGe)2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ba is bonded in a 8-coordinate geometry to eight equivalent Cd and eight equivalent Ge atoms. All Ba–Cd bond lengths are 3.75 Å. All Ba–Ge bond lengths are 3.61 Å. Cd is bonded to four equivalent Ba and four equivalent Ge atoms to form a mixture of distorted face, edge, and corner-sharing CdBa4Ge4 tetrahedra. All Cd–Ge bond lengths are 2.87 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Ba, four equivalent Cd, and one Ge atom. The Ge–Ge bond length is 2.60 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CdHg3 by Materials Project

Hg3Cd crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Hg sites. In the first Hg site, Hg is bonded in a 8-coordinate geometry to four equivalent Hg and four equivalent Cd atoms. All Hg–Hg bond lengths are 3.29 Å. All Hg–Cd bond lengths are 3.47 Å. In the second Hg site, Hg is bonded in a square co-planar geometry to four equivalent Cd atoms. All Hg–Cd bond lengths are 3.29 Å. Cd is bonded to twelve Hg atoms to form a mixture of distorted face, edge, and corner-sharing CdHg12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AcLaCd2 by Materials Project

AcLaCd2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ac is bonded in a body-centered cubic geometry to eight equivalent Cd atoms. All Ac–Cd bond lengths are 3.48 Å. La is bonded in a body-centered cubic geometry to eight equivalent Cd atoms. All La–Cd bond lengths are 3.48 Å. Cd is bonded in a body-centered cubic geometry to four equivalent Ac and four equivalent La atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd2AgPt by Materials Project

PtAgCd2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pt is bonded in a body-centered cubic geometry to eight equivalent Cd atoms. All Pt–Cd bond lengths are 2.89 Å. Ag is bonded in a distorted body-centered cubic geometry to eight equivalent Cd atoms. All Ag–Cd bond lengths are 2.89 Å. Cd is bonded in a body-centered cubic geometry to four equivalent Pt and four equivalent Ag atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li2MgCd by Materials Project

Li2MgCd crystallizes in the cubic F-43m space group. The structure is three-dimensional. there are two inequivalent Li sites. In the first Li site, Li is bonded in a 4-coordinate geometry to four equivalent Mg atoms. All Li–Mg bond lengths are 2.95 Å. In the second Li site, Li is bonded to four equivalent Cd atoms to form distorted corner-sharing LiCd4 tetrahedra. All Li–Cd bond lengths are 2.95 Å. Mg is bonded in a body-centered cubic geometry to four equivalent Li and four equivalent Cd atoms. All Mg–Cd bond lengths are 2.95 Å. Cd is bonded in a body-centered cubic geometry to four equivalent Li and four equivalent Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TmCdNi4 by Materials Project

TmNi4Cd is Hexagonal Laves-derived structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Tm is bonded in a 12-coordinate geometry to twelve equivalent Ni and four equivalent Cd atoms. All Tm–Ni bond lengths are 2.90 Å. All Tm–Cd bond lengths are 3.02 Å. Ni is bonded to three equivalent Tm, six equivalent Ni, and three equivalent Cd atoms to form a mixture of corner, edge, and face-sharing NiTm3Cd3Ni6 cuboctahedra. There are three shorter (2.45 Å) and three longer (2.48 Å) Ni–Ni bond lengths. All Ni–Cd bond lengths are 2.89 Å. Cd is bonded in a 4-coordinate geometry to four equivalent Tm and twelve equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2CdP3O11 by Materials Project

Ba2CdP3O11 crystallizes in the monoclinic Cm space group. The structure is three-dimensional. there are two inequivalent Ba sites. In the first Ba site, Ba is bonded in a 10-coordinate geometry to ten O atoms. There are a spread of Ba–O bond distances ranging from 2.79–3.08 Å. In the second Ba site, Ba is bonded in a 12-coordinate geometry to twelve O atoms. There are a spread of Ba–O bond distances ranging from 2.82–3.38 Å. Cd is bonded to six O atoms to form distorted CdO6 pentagonal pyramids that share corners with four PO4 tetrahedra and an edgeedge with one PO4 tetrahedra. There are a spread of Cd–O bond distances ranging from 2.29–2.46 Å. There are three inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share an edgeedge with one CdO6 pentagonal pyramid. There is two shorter (1.55 Å) and two longer (1.56 Å) P–O bond length. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent CdO6 pentagonal pyramids and a cornercorner with one PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.51–1.63 Å. In the third P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent CdO6 pentagonal pyramids and a cornercorner with one PO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.52–1.62 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a distorted single-bond geometry to two Ba, one Cd, and one P atom. In the second O site, O is bonded in a 1-coordinate geometry to two Ba, one Cd, and one P atom. In the third O site, O is bonded in a 1-coordinate geometry to two Ba, one Cd, and one P atom. In the fourth O site, O is bonded in a distorted single-bond geometry to three Ba and one P atom. In the fifth O site, O is bonded in a distorted single-bond geometry to three Ba and one P atom. In the sixth O site, O is bonded in a distorted single-bond geometry to three Ba and one P atom. In the seventh O site, O is bonded in a single-bond geometry to one Ba and one P atom. In the eighth O site, O is bonded in a bent 120 degrees geometry to two P atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Er2CdGe2 by Materials Project

Er2CdGe2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Er is bonded in a 6-coordinate geometry to four equivalent Cd and six equivalent Ge atoms. All Er–Cd bond lengths are 3.39 Å. There are two shorter (2.93 Å) and four longer (3.05 Å) Er–Ge bond lengths. Cd is bonded to eight equivalent Er and four equivalent Ge atoms to form a mixture of distorted face and corner-sharing CdEr8Ge4 cuboctahedra. All Cd–Ge bond lengths are 2.88 Å. Ge is bonded in a 9-coordinate geometry to six equivalent Er, two equivalent Cd, and one Ge atom. The Ge–Ge bond length is 2.52 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Elucidating structure and dynamics of crystalline α-zirconium phosphates intercalated with water and methanol by multinuclear solid-state MAS NMR: A comprehensive NMR approach

Solid-state NMR experiments on 2 H, 31 P, 13 C, and 1 H nuclei, including 31 P T 1 , 1 H T 1 , and 1 H T 1ρ measurements, as well as on the kinetics of proton-phosphorus cross-polarization have been performed to characterize the crystalline and amorphous α-zirconium phosphates, which were intercalated with D 2 O and/or CD 3 OD. The 13 C{ 1 H} CP MAS NMR experiment performed for compound 1-CD 3 OD (Zr (HPO 4 ) 2 .0.2CD 3 OD) with carbon cross-polarization via protons of phosphate groups has provided a prove that the methanol was intercalated into the interlayer spaces of this compound. The variable-temperature 2 H solid-echo MAS NMR spectra of intercalated compounds demonstrated that the methanol molecules, in contrast to the mobile water, were immobile, keeping, however, free CD 3 rotations around the C 3 -axis. It has been demonstrated that the intercalated species, D 2 O and CD 3 OD, do not affect the high-frequency motions of the phosphate groups. By utilizing local structural models that satisfy the constraints of the experimental data, it has been suggested that the immobile methanol molecules are located in the cavity between two neighboring layers of the zirconium phosphates. Here, the present work illustrates the reliable criteria in a comprehensive NMR approach to structural and dynamic studies of such systems.

1H↗
DOE OSTI2022

Comparing the extraction performance of cyclodextrin-containing supramolecular deep eutectic solvents versus conventional deep eutectic solvents by headspace single drop microextraction

A headspace single drop microextraction (HS-SDME) method coupled with high performance liquid chromatography was developed to compare the extraction of eighteen aromatic organic pollutants from aqueous solutions using cyclodextrin-based supramolecular deep eutectic solvents (SUPRADESs) and alkylammonium halide-based conventional deep eutectic solvents (DESs). Different derivatives of beta-cyclodextrin (β-CD) were employed as hydrogen bond acceptors (HBA) in SUPRADESs and the extraction performance investigated. SUPRADES comprised of the 20 wt% native β-CD HBA provided the highest enrichment factors of analytes compared to SUPRADESs comprised of other derivatives of β-CD (random methylated β-cyclodextrin, heptakis(2,3,6-tri-O-methyl)-β-cyclodextrin, and 2-hydroxypropyl β-cyclodextrin). In addition, native β-CD and its derivatives were dissolved in the neat DESs and their effect on the extraction of analytes examined. Dissolution of 20 wt% native β-CD in the choline chloride ([Ch + ][Cl - ]):2Urea DES resulted in a significant increase in the extraction efficiencies of target analytes compared to the neat [Ch + ][Cl - ]:2Urea DES. Under optimum conditions, the extraction method required a solvent microdroplet of 6.5 μL, 1000 rpm stir rate, 30% (w/v) salt concentration, and a temperature of 40 °C. The tetrabutylammonium chloride: 2 lactic acid DES resulted in the highest enrichment factors while the [Ch + ][Cl - ]:2Urea DES had the lowest for most of the analytes among the evaluated solvents. The method provided limits of detection (LODs) down to 35 μg L -1 . Finally, the developed method was applied for the analysis of spiked tap and lake water, where relative recoveries ranging from 83.7% -119.7% and relative standard deviations lower than 19.2% were achieved.

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

Mid-infrared chiral metasurface absorbers with split-ellipse structures

Natural chiral materials usually have very weak circular dichroism (CD) responses. Here, in this study, we design and demonstrate one type of mid-infrared chiral metasurface absorber with strong chiroptical effects, which can achieve high CD in absorption above 0.57 over the wavelength range of 5 to 5.9 μm. The maximum absorption of the chiral metasurface absorber under circularly polarized light can reach 0.90 and the maximum CD in absorption is 0.63. Meanwhile, the chiral resonance wavelength and the CD value can be tuned by varying the geometric parameters of the metasurface. A thermal analysis of the metasurface absorber further shows the strong connection between CD in absorption and temperature difference. The demonstrated chiral metasurface absorbers can be used in many promising applications such as molecular sensing, thermophotovoltaics and chiral spectroscopy.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Data-Driven Mapping of the Cesium Cadmium Bromide Phase Space Utilizing a Soft-Chemistry Approach

Soft-chemistry techniques provide a versatile approach to synthesizing inorganic materials under mild conditions, enabling access to compositions and structures that are challenging to achieve through traditional thermodynamically driven solid-state methods. However, these solution-based routes often result in phase competition, requiring precise control over reaction conditions to achieve selective product formation. While one-variable-at-a-time (OVAT) approaches have traditionally been used for phase selection, data-driven strategies are emerging as more efficient methods for navigating complex synthetic spaces. Ternary metal halides, such as cesium cadmium bromides (Cs–Cd–Br), are of growing interest due to their potential in wide and ultrawide band gap applications. Unlike the well-studied cesium lead halide phases, the compositional diversity and solution-based synthesis of ternary Cs–Cd–Br phases remain largely unexplored. This study systematically investigates the synthetic phase space of the Cs–Cd–Br system by constructing a data-driven phase map. Using a common set of precursors and a standardized experimental procedure, we successfully synthesize all four known Cs–Cd–Br phases—CsCdBr 3 , Cs 2 CdBr 4 , Cs 3 CdBr 5 , and Cs 7 Cd 3 Br 13 —each exhibiting distinct structures, morphologies, and optical properties. Our findings highlight the potential of soft-chemistry methods for expanding the library of ternary metal halides and provide key insights into the thermodynamic and kinetic factors governing phase formation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Cyclodextrin-Derived Porous Liquids Enabled by In Situ Solvation Shell Formation

Porous liquids (PLs) represent a unique platform for molecular separations by combining permanent porosity with liquid-phase mobility. However, it remains a formidable challenge to construct and stabilize PLs with sub-5 Å pores using readily available porous host and liquid media. Here, we report the construction of cyclodextrin (CD)-derived PLs enabled by in situ solvation shell formation. The acid–base neutralization reaction between CD and an organic base was leveraged to generate a thin ionic solvation shell around the CD host, effectively liquefying CD and preventing its segregation in the liquid base medium while preserving accessible molecular-scale cavities. Spectroscopic analysis, neutron scattering, density functional theory calculations, and molecular dynamics simulations collectively confirm the structural evolution and existence of abundant internal porosity in PLs. The unique architectures of CD-derived PLs enable highly selective encapsulation of fluorinated alkanes and significantly enhanced uptake of inert gases. This facile and generalizable strategy enables construction of high-quality PLs with engineered ultramicroporosity to facilitate molecular separations.

Cavities↗
DOE OSTI2022

Impact of dopant-induced band tails on optical spectra, charge carrier transport, and dynamics in single-crystal CdTe

Abstract Cadmium telluride (CdTe) semiconductors are used in thin-film photovoltaics, detectors, and other optoelectronic applications. For all technologies, higher efficiency and sensitivity are achieved with reduced charge carrier recombination. In this study, we use state-of-the-art CdTe single crystals and electro-optical measurements to develop a detailed understanding of recombination rate dependence on excitation and temperature in CdTe. We study recombination and carrier dynamics in high-resistivity (undoped) and arsenic (As)-doped CdTe by employing absorption, the Hall effect, time-resolved photoluminescence, and pump-probe in the 80–600 K temperature range. We report extraordinarily long lifetimes (30 µs) at low temperatures in bulk undoped CdTe. Temperature dependencies of carrier density and mobility reveal ionization of the main acceptors and donors as well as dominant scattering by ionized impurities. We also distinguish different recombination defects. In particular, shallow As Te and deep V Cd −As Cd acceptors were responsible for p-type conductivity. AX donors were responsible for electron capture, while nonradiative recombination centers (V Cd −As Te , As 2 precipitates), and native defects (V Cd −Te Cd ) were found to be dominant in p-type and n-type CdTe, respectively. Bimolecular and surface recombination rate temperature dependencies were also revealed, with bimolecular coefficient T −3/2 temperature dependence and 170 meV effective surface barrier, leading to an increase in surface recombination velocity at high temperatures and excitations. The results of this study allowed us to conclude that enhanced crucible rotation growth of As-doped CdTe is advantageous to As activation, leading to longer lifetimes and larger mobilities and open-circuit voltages due to lower absorption and trapping.

36 MATERIALS SCIENCE↗
DOE OSTI2025

The balance of orbital overlap and orbital energy in the activation of methane by actinide cations: insights from inductively coupled plasma tandem mass spectrometry

The actinides present a unique challenge to chemical theory. The classical view of covalent bonding is driven by the extent of spatial overlap of valence orbitals. Modern theory has expanded assessments of covalency to include considerations of orbital energy degeneracy to assess orbital energy mixing between metal and ligand valence orbitals. Actinide–ligand (An–L) bonding has more recently been described as a balance between orbital overlap and orbital energy mixing, where 5f and L valence orbital overlap decreases while energy mixing between An 5f and L valence orbitals increases across the series. To test these existing views, we employed inductively coupled plasma tandem mass spectrometry to examine the kinetic energy dependences of reactions of actinide cations, Th + –Am + , with methane. Further, this is the first experimental report of the energy dependences of methane activation reactions involving the cations of Pa, Np, Pu, and Am and the first experimental determination of transuranic An + –D, An + –CD 2 , An + –CD 3 , and An + –CD bond dissociation energies. The correlation of the measured An + –CD 2 bond energies with E p (6d 2 ) indicates that An + 6d orbitals are the dominant contributors in the An + –CD 2 bonds. Close examination of the relative reactivities of An + offers additional support that the balance of classical and modern views of molecular bonding may lie between Np + and Pu + and that the increased reactivity of Th + –Np + may be attributed to the increased spatial extension of the 5f orbitals whereas covalent An + bond formation may be more driven by the decreasing energies of the 5f orbitals across the actinide series.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗