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All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

From +I to +IV, Alkalis to Actinides: Capturing Cations across the Periodic Table with Keggin Polyoxometalate Ligands

Coordination chemistry trends across the periodic table are often difficult to probe experimentally due to limitations in finding a versatile but consistent chelating platform that can accommodate various elements without changing its coordination mode. Herein, we present new metal/ligand systems covering a wide range of ionic radii, charges, and elements. Five different ligands derived from the Keggin structure (HBW 11 O 39 8– , PW 11 O 39 7– , SiW 11 O 39 8– , GeW 11 O 39 8– , and GaW 11 O 39 9– ) were successfully crystallized with six different cations (Na + , Sr 2+ , Ba 2+ , La 3+ , Ce 4+ , and Th 4+ ) and characterized by single-crystal X-ray diffraction. Twenty-five new compounds were obtained by using Cs + as the counterion, yielding a consistent base formula of Cs x [M(XW 11 O 39 ) 2 ]·nH 2 O. Despite having a similar first-coordination sphere geometry (i.e., 8-coordinated), the nature of the central cation was found to impact the long-range geometry of the complexes. This unique crystallographic data set shows that, despite the traditional consensus, the local geometry of the cation (i.e., metal–oxygen bond distance) is not enough to depict the full impact of the complexed metal ion. The bending and twisting of the complexes, as well as ligand–ligand distances, were all impacted by the nature of the central cation. We also observed that counterions play a critical role by stabilizing the geometry of the M(XW 11 ) 2 complex and directing complex–complex interactions in the lattice. We also define certain structural limits for this type of complex, with the large Ba 2+ ion seemingly approaching those limits. Finally, this study thus lays the foundation for capturing the coordination chemistry of other rarer elements across the periodic table such as Ra 2+ , Ac 3+ , Bk 4+ , Cf 3+ , etc.

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

Reaction Pathways over ZnZrO 2 -Based Catalysts and Catalytic Sorbents

Reactive capture and conversion (RCC) is a process intensification approach that integrates CO 2 capture and hydrogenation within a single unit, removing the CO 2 purification and storage steps of traditional process flow schemes. This alters the catalytic step from a traditional steady-state (SS) flow process to a transient capture and conversion cycle, which could lead to product distributions distinct from those observed in conventional SS experiments. Such differences are investigated in the combined capture and hydrogenation of carbon dioxide to methanol over a ZnZrO 2 catalyst and a ZnZrO 2 + NaNO 3 /Mg 3 AlO x catalytic sorbent (CS) using fixed-bed kinetic measurements, in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and steady-state isotopic transient kinetic analysis-DRIFTS (SSITKA-DRIFTS). Under SS conditions, ZnZrO 2 produced methanol through sequential hydrogenation of HCOO* and CH 3 O* intermediates. On the contrary, CO was attributed primarily to CO 2 dissociation at oxygen vacancies, as supported by isotopic shifts and measured reaction orders. For the CS, isotopic switching experiments suggested that monodentate carbonate species (CO 3 2− , abbreviated as m-CO 3 2− ) act as active intermediates that can be hydrogenated to HCOO* and subsequently to CH 3 O. Under RCC conditions, in situ DRIFTS and isotopic experiments reveal that m-CO 3 2− species formed during the CO 2 capture step follow two competing routes upon H 2 exposure: (i) direct hydrogenation to methane on the sorbent domain or (ii) migration of m-CO 3 2− to the ZnZrO 2 domain, where they are hydrogenated to methanol through the HCOO pathway. Overall, RCC enables carbonate hydrogenation routes not observed under SS cofeed conditions. Thus, the reaction pathways and rates during RCC can be different from operation under conventional SS conditions, and the product distribution is determined here by competition between carbonate hydrogenation on sorbent sites and migration to ZnZrO 2 for methanol synthesis.

CCUS↗
DOE OSTI2020

Materials Data on CsVGa(PO5)2 by Materials Project

CsVGa(PO5)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Cs is bonded in a 11-coordinate geometry to eleven O atoms. There are a spread of Cs–O bond distances ranging from 3.10–3.65 Å. V is bonded to six O atoms to form VO6 octahedra that share corners with four PO4 tetrahedra. There are a spread of V–O bond distances ranging from 1.65–2.05 Å. Ga is bonded to four O atoms to form GaO4 tetrahedra that share corners with four PO4 tetrahedra. There are a spread of Ga–O bond distances ranging from 1.82–1.87 Å. There are two inequivalent P sites. In the first P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent VO6 octahedra and corners with two equivalent GaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–45°. There are a spread of P–O bond distances ranging from 1.53–1.56 Å. In the second P site, P is bonded to four O atoms to form PO4 tetrahedra that share corners with two equivalent VO6 octahedra and corners with two equivalent GaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–49°. There are a spread of P–O bond distances ranging from 1.53–1.56 Å. There are ten inequivalent O sites. In the first O site, O is bonded in a 2-coordinate geometry to one Cs, one V, and one P atom. In the second O site, O is bonded in a 2-coordinate geometry to two equivalent Cs, one V, and one P atom. In the third O site, O is bonded in a bent 150 degrees geometry to one Ga and one P atom. In the fourth O site, O is bonded in a distorted bent 120 degrees geometry to one Cs, one Ga, and one P atom. In the fifth O site, O is bonded in a 2-coordinate geometry to one Cs, one Ga, and one P atom. In the sixth O site, O is bonded in a distorted bent 150 degrees geometry to one Cs, one V, and one P atom. In the seventh O site, O is bonded in a single-bond geometry to two equivalent Cs and one V atom. In the eighth O site, O is bonded in a distorted bent 150 degrees geometry to one Cs, one V, and one P atom. In the ninth O site, O is bonded in a bent 120 degrees geometry to one Cs, one Ga, and one P atom. In the tenth O site, O is bonded in a single-bond geometry to one Cs and one V atom.

36 MATERIALS SCIENCE↗
NASA NTRS2016

Magnetospheric Multiscale Observations of Magnetic Reconnection Associated with Kelvin-Helmholtz Waves

The four Magnetospheric Multiscale (MMS) spacecraft recorded the first direct evidence of reconnection exhausts associated with Kelvln-Helmholtz (KH) waves at the duskside magnetopause on 8 September 2015 which allows for local mass and energy transport across the flank magnetopause. Pressure anisotropy-weighted Walen analyses confirmed in-plane exhausts across 22 of 42 KH-related trailing magnetopause current sheets (CSs). Twenty-one jets were observed by all spacecraft, with small variations in ion velocity, along the same sunward or antisunward direction with nearly equal probability. One exhaust was only observed by the MMS-1,2 pair, while MMS-3,4 traversed a narrow CS (1.5 ion inertial length) in the vicinity of an electron diffusion region. The exhausts were locally 2-D planar in nature as MMS-1, 2 observed almost identical signatures separated along the guide-field. Asymmetric magnetic and electric Hall fields are reported in agreement with a strong guide-field and a weak plasma density asymmetry across the magnetopause CS.

Eriksson, S.↗
DOE OSTI2022

Test of nuclear decay rate variation due to an antineutrino flux

Unexplained variations of the decay rate parameter for weak interaction decays such as β ± decay, electron capture, as well as strong interaction α decay have been reported. Because these variations have been presented by a number of groups, at various locations, using various types of detectors, different isotopes, and over extended periods of time, some researchers have interpreted the source of these variations as not from ambient environmental factors such as temperature, pressure, and humidity but via an unexplained fundamental interaction. The state of decay rate parameter variations experiments is reviewed, and the reported results are placed into a common comparable context by defining a phenomenological cross section. After that we make decay parameter measurements as a function of time at the level of 10 -5 in the presences of an antineutrino flux with an on-off cycle time of ≈ 30 days. This level of precision requires a detailed understanding of both systematic and statistical errors; otherwise, systematic errors in the measurement may mimic the decay events of fundamental interactions. The experiment searched for variation of the $^{54}_{25}$Mn, e - capture decay rate parameter and $^{137}_{55}$Cs, β - decay rate parameter both to a level of precision of 1 part in ≈10 5 by comparing the difference between the decay rate in the presence of an antineutrino flux ≈ 3 x 10 12 $\bar{ν}$ cm -2 s -1 and no flux measurements. The experiment was located 6.53 m from the reactor core of the High Flux Isotope Reactor at the Oak Ridge National Laboratory. Two weak interaction decays, one via electron capture and the other via β - decay, were selected because the final state and the time reverse state each contain a neutrino and antineutrino, covering arguments that the antineutrino flux may interact differently or not at all in one of the cases. The $\gamma$ spectra from both decays were collected and analyzed independently. The measured variation in the decay rate parameters are found to be δλ/λ =(0.034 ± 1.38) x10 -5 for $^{54}_{25}$Mn and δλ/λ =(0.67±1.56) x10 -5 for $^{137}_{55}$Cs. These results are consistent with no measurable decay rate parameter variation due to an antineutrino flux, yielding a 68% confidence level upper limit sensitivity for $^{54}_{25}$Mn δλ/λ ≤ 1.31 x 10 -5 or σ ≤ 1.29 x10 -25 cm 2 in cross section and for $^{137}_{55}$Cs δλ/λ ≤ 2.23 x 10 -5 or σ ≤ 5.69 x10 -27 cm 2 . The cross-section upper limit obtained in these null or no observable effect measurements are ≈ 10 4 times more sensitive than past experiments reporting positive results in 54 Mn and 137 Cs. . .

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS2000

Spaceflight effects on single skeletal muscle fiber function in the rhesus monkey

The purpose of this investigation was to understand how 14 days of weightlessness alters the cellular properties of individual slow- and fast-twitch muscle fibers in the rhesus monkey. The diameter of the soleus (Sol) type I, medial gastrocnemius (MG) type I, and MG type II fibers from the vivarium controls averaged 60 +/- 1, 46 +/- 2, and 59 +/- 2 microm, respectively. Both a control 1-G capsule sit (CS) and spaceflight (SF) significantly reduced the Sol type I fiber diameter (20 and 13%, respectively) and peak force, with the latter declining from 0.48 +/- 0.01 to 0.31 +/- 0.02 (CS group) and 0.32 +/- 0.01 mN (SF group). When the peak force was expressed as kiloNewtons per square meter (kN/m(2)), only the SF group showed a significant decline. This group also showed a significant 15% drop in peak fiber stiffness that suggests that fewer cross bridges were contracting in parallel. In the MG, SF but not CS depressed the type I fiber diameter and force. Additionally, SF significantly depressed absolute (mN) and relative (kN/m(2)) force in the fast-twitch MG fibers by 30% and 28%, respectively. The Ca(2+) sensitivity of the type I fiber (Sol and MG) was significantly reduced by growth but unaltered by SF. Flight had no significant effect on the mean maximal fiber shortening velocity in any fiber type or muscle. The post-SF Sol type I fibers showed a reduced peak power and, at peak power, an elevated velocity and decreased force. In conclusion, CS and SF caused atrophy and a reduced force and power in the Sol type I fiber. However, only SF elicited atrophy and reduced force (mN) in the MG type I fiber and a decline in relative force (kN/m(2)) in the Sol type I and MG type II fibers.

Non-NASA Center↗
DOE OSTI2020

Potential for Transport of Cesium as Bio-colloids in a High Ionic Strength System

The Waste Isolation Pilot Plant (WIPP) is a deep geologic repository for long-term disposal of transuranic, radioactive waste that is a byproduct from the nation's nuclear defense program. Most likely release scenario → human intrusion (potentially through drilling) (US DOE 1995; 1996). Brine may proceed through the Rustler formation (the most transmissive layer) (Perkins et al., 1999). There is a need to investigate halophilic microbes including their mobility in the Rustler formation and the potential for enhancing transport of cesium as a bio-colloid. Objectives: To quantify the change in mobility of Cs by interaction with microbes (Chromohalobacter) that may be present near Waste Isolation Pilot Plant. What is Chromohalobacter?: a halophilic microbe, isolated from near the WIPP site, able to thrive in the high salt concentrations relevant to the repository. Does the microbe growth phase effect uptake of Cs? Experiments conducted with actively growing and stationary phase Chromohalobacter. Uptake may differ if Cs{sup +} is mistaken for K{sup +} in an actively growing (Log) phase versus stationary phase microbes (not actively reproducing). Materials: 1'' Teflon column packed with 1 gram of dolomite [355-500 μm, CaMg(CO{sub 3}){sub 2}] connected to a syringe pump and fraction collector via Teflon tubing. Chromohalobacter (100 million cells/mL) and dolomite collected near the WIPP. Synthetic brine - 15% NaCl (w/v ∼2.78 M) + 3 mM NaHCO{sub 3}. Methodology: Negative Control 5,000 ppb Cs initially injected into mini-columns with brine. Injection solution was then switched to only brine. Cs Experiments with Stationary Phase Chromo: Set 1: Viable stationary Chromo injected into minicolumns after reaction with 200 ppb Cs. Injection solution was then switched to only brine (without Cs or microbes). Set 2: Stressed stationary Chromo initially injected into mini-columns after reaction with 200 ppb Cs. Then, switched to brine only. Cs Experiments with Log phase Chromo: Set 1: Chromo injected into mini-columns after reaction with 5,000 ppb Cs. Injection then switched to only brine (without Cs or microbes). Set 2: Chromo grown with 5,000 ppb Cs and spiked with additional Cs before injection into columns. Preliminary Conclusions: Cs was not taken up or mobilized by Chromohalobacter in the actively growing or stationary phases or under stressed conditions. Competition may have occurred between Cs and K{sup +} at lower ionic strength, significantly greater concentrations of K{sup +} were present. Results suggest that Chromohalobacter can selectively uptake K{sup +} in the presence of Cs{sup +}. Future Research: K{sup +} and Cs{sup +} uptake will be monitored at high ionic strength in K{sup +} depleted media to consider uptake of Cs in the absence of K.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Ion Exchange Processing of AP-105 Hanford Tank Waste through Crystalline Silicotitanate in a Staged 2- then 3-Column System (Rev.1)

The Tank Side Cesium Removal (TSCR) system, under development by Washington River Protection Solutions LLC (WRPS), will send initial low-activity Hanford waste tank supernate feeds to the Hanford Waste Treatment and Immobilization Plant (WTP) Low-Activity Waste (LAW) Facility. In addition to entrained solids removal from the supernate, the primary goal of TSCR is to remove cesium-137 ( 137 Cs) by ion exchange, allowing contact handling of the liquid effluent product at the WTP. Crystalline silicotitanate (CST) ion exchange media, manufactured by Honeywell UOP, LLC (product IONSIVTM R9140-B), was selected as the ion exchange media at TSCR. CST is a non-elutable inorganic material that has demonstrated robust chemical, physical, and radiation tolerance while maintaining functionality. However, exchange kinetics of Cs onto CST is slow, resulting in low utilization of the CST Cs load capacity before unacceptable Cs breakthrough. Two process flow designs have been tested, as follows. 1. Lead-lag column processing: The lead column was removed after the lag column effluent reached the waste acceptance criteria (WAC) limit, the lag column was moved into the lead position, and a new lag column was installed. This format used ~52% Cs load capacity on the lead column. 2. Lead-lag-polish column processing: The processing was stopped when the polish column effluent reached the WAC limit. This format resulted in 81% Cs load capacity on the lead column. Testing with diluted feed from Hanford tank AP-105 (AP-105DF) incorporated a nuanced change to the lead-lag-polish column system where the polish column was inserted when the lag column effluent reached WAC limit. A 10.9-L volume of AP-105DF (diluted to 5.6 M Na) was processed through the Direct Feed Test Platform system, established at Pacific Northwest National Laboratory to support small-scale waste qualification efforts. The columns consisted of 10-mL CST beds (CST Lot 2002009604, sieved to screen out >30-mesh particles) placed in 1.5-cm-inner-diameter columns. Feed was processed at 1.83 bed volumes (BV) per hour; the flowrate, in terms of contact time with the CST bed, matched the expected flowrate at TSCR. The <30-mesh CST sieve cut was expected to provide appropriate performance scaling to a full-height column. The installation of the polish column later in processing (after processing 523 BVs) did not appear to fundamentally change the utilization of the lead column for Cs exchange nor did it extend the total feed processing volume when compared to the previous test with AP-107 feed. Table ES.1 and Figure ES.1 summarize the measured AP-105DF Cs load performance.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

Materials Data on Cs7(FeS2)4 by Materials Project

Cs7(FeS2)4 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are four inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to eight S2- atoms. There are a spread of Cs–S bond distances ranging from 3.54–3.85 Å. In the second Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to six S2- atoms. There are a spread of Cs–S bond distances ranging from 3.49–4.11 Å. In the third Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to seven S2- atoms. There are a spread of Cs–S bond distances ranging from 3.50–3.95 Å. In the fourth Cs1+ site, Cs1+ is bonded to four S2- atoms to form distorted CsS4 tetrahedra that share corners with two equivalent CsS4 tetrahedra, corners with four FeS4 tetrahedra, and an edgeedge with one CsS4 tetrahedra. There are a spread of Cs–S bond distances ranging from 3.48–3.57 Å. There are two inequivalent Fe+2.25+ sites. In the first Fe+2.25+ site, Fe+2.25+ is bonded to four S2- atoms to form FeS4 tetrahedra that share corners with two equivalent CsS4 tetrahedra and edges with three FeS4 tetrahedra. There are a spread of Fe–S bond distances ranging from 2.25–2.40 Å. In the second Fe+2.25+ site, Fe+2.25+ is bonded to four S2- atoms to form FeS4 tetrahedra that share corners with two equivalent CsS4 tetrahedra and edges with three FeS4 tetrahedra. There are a spread of Fe–S bond distances ranging from 2.24–2.41 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded in a 3-coordinate geometry to four Cs1+ and three Fe+2.25+ atoms. In the second S2- site, S2- is bonded in a 7-coordinate geometry to four Cs1+ and three Fe+2.25+ atoms. In the third S2- site, S2- is bonded in a 1-coordinate geometry to six Cs1+ and one Fe+2.25+ atom. In the fourth S2- site, S2- is bonded in a 1-coordinate geometry to seven Cs1+ and one Fe+2.25+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Ion Exchange of Selected Group II Metals and Lead by Crystalline Silicotitanate and Competition for Cs Exchange Sites

A series of batch contact tests were conducted to evaluate the exchange behavior of Ba, Ca, Pb, and Sr onto crystalline silicotitanate (CST) in support of an expedited Cs removal and pretreatment system at the Hanford site. Binary Na/M 2+ and ternary Na/Cs/M 2+ isotherms were generated to understand selectivity, capacity, and competitive impact of each analyte on Cs uptake from a simple 1 M NaOH/4.6 M NaNO 3 simulant. Analyte loading from a 0.1 M NaOH/5.5 M NaNO 3 simulant was assessed to determine the effect of hydroxide concentration on binary Na/M 2+ isotherms. Finally, results from binary and ternary isotherms indicated that group II metals, and Pb do not impact CST performance toward CST at concentrations expected in Hanford tank waste supernate.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on Cs10Ge2O9 by Materials Project

Cs10Ge2O9 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are ten inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Cs–O bond distances ranging from 2.83–3.37 Å. In the second Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Cs–O bond distances ranging from 2.94–3.42 Å. In the third Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cs–O bond distances ranging from 2.74–3.37 Å. In the fourth Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to seven O2- atoms. There are a spread of Cs–O bond distances ranging from 2.85–3.53 Å. In the fifth Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Cs–O bond distances ranging from 2.77–3.43 Å. In the sixth Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cs–O bond distances ranging from 2.99–3.27 Å. In the seventh Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cs–O bond distances ranging from 2.90–3.00 Å. In the eighth Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cs–O bond distances ranging from 3.04–3.45 Å. In the ninth Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Cs–O bond distances ranging from 2.91–3.30 Å. In the tenth Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to two O2- atoms. There are one shorter (2.76 Å) and one longer (3.01 Å) Cs–O bond lengths. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Ge–O bond distances ranging from 1.80–1.82 Å. In the second Ge4+ site, Ge4+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Ge–O bond distances ranging from 1.80–1.82 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to six Cs1+ and one Ge4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to five Cs1+ and one Ge4+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to four Cs1+ and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to four Cs1+ and one Ge4+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to four Cs1+ and one Ge4+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to five Cs1+ and one Ge4+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to five Cs1+ and one Ge4+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to six Cs1+ and one Ge4+ atom. In the ninth O2- site, O2- is bonded in a distorted pentagonal planar geometry to five Cs1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Crystal Growth, Optical and Scintillation Properties of Eu 2+ -doped TlSr 2 Br 5

Crystals of undoped and Eu 2+ -doped TlSr 2 Br 5 of up to 16 mm in diameter and 50 mm in length were grown by the Vertical Bridgman technique. TlSr 2 Br 5 has the monoclinic crystal structure with space group P21/c. Its density and Z eff are 5.03 g/cm 3 and 58.6, respectively. Radioluminescence spectra of undoped and Eu 2+ -doped TlSr 2 Br 5 feature a broad emission band peaking at about 440 nm for undoped and 520 nm for Eu 2+ -doped crystals. The light yield of undoped TlSr 2 Br 5 is 42,000 ph/MeV, which increases to 55,000 ph/MeV for Eu 2+ -doped crystals. The energy resolution at 662 keV ( 137 Cs) is about 5 – 6% (FWHM). As a result, the scintillation decay of undoped and Eu 2+ -doped TlSr 2 Br 5 is of the order of 100s of nanoseconds.

Bridgman technique↗
DOE OSTI2020

Materials Data on Cs4TeSe15 by Materials Project

Cs4TeSe15 crystallizes in the orthorhombic Pbcm space group. The structure is three-dimensional. there are four inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten Se+0.53- atoms. There are a spread of Cs–Se bond distances ranging from 3.67–4.27 Å. In the second Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to eight Se+0.53- atoms. There are a spread of Cs–Se bond distances ranging from 3.69–4.28 Å. In the third Cs1+ site, Cs1+ is bonded in a 8-coordinate geometry to ten Se+0.53- atoms. There are a spread of Cs–Se bond distances ranging from 3.66–4.32 Å. In the fourth Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to ten Se+0.53- atoms. There are a spread of Cs–Se bond distances ranging from 3.69–4.10 Å. Te4+ is bonded in a square co-planar geometry to four Se+0.53- atoms. There are two shorter (2.74 Å) and two longer (2.97 Å) Te–Se bond lengths. There are eight inequivalent Se+0.53- sites. In the first Se+0.53- site, Se+0.53- is bonded in a 5-coordinate geometry to three Cs1+ and two Se+0.53- atoms. Both Se–Se bond lengths are 2.38 Å. In the second Se+0.53- site, Se+0.53- is bonded in a 3-coordinate geometry to two equivalent Cs1+ and two equivalent Se+0.53- atoms. Both Se–Se bond lengths are 2.39 Å. In the third Se+0.53- site, Se+0.53- is bonded in a 1-coordinate geometry to three Cs1+, one Te4+, and two Se+0.53- atoms. There are one shorter (2.38 Å) and one longer (3.45 Å) Se–Se bond lengths. In the fourth Se+0.53- site, Se+0.53- is bonded in a 6-coordinate geometry to four Cs1+ and two Se+0.53- atoms. The Se–Se bond length is 3.17 Å. In the fifth Se+0.53- site, Se+0.53- is bonded in a 3-coordinate geometry to two Cs1+ and two Se+0.53- atoms. The Se–Se bond length is 2.41 Å. In the sixth Se+0.53- site, Se+0.53- is bonded in a 1-coordinate geometry to two Cs1+, one Te4+, and two Se+0.53- atoms. The Se–Se bond length is 2.41 Å. In the seventh Se+0.53- site, Se+0.53- is bonded in a 4-coordinate geometry to two Cs1+ and two Se+0.53- atoms. In the eighth Se+0.53- site, Se+0.53- is bonded in a 3-coordinate geometry to two Cs1+ and three Se+0.53- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2Ca(Cl2O)2 by Materials Project

Cs2Ca(OCl2)2 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Cs is bonded in a 9-coordinate geometry to two equivalent O and seven Cl atoms. There are one shorter (3.26 Å) and one longer (3.51 Å) Cs–O bond lengths. There are a spread of Cs–Cl bond distances ranging from 3.45–3.97 Å. Ca is bonded in an octahedral geometry to two equivalent O and four Cl atoms. Both Ca–O bond lengths are 2.32 Å. There are two shorter (2.72 Å) and two longer (2.90 Å) Ca–Cl bond lengths. O is bonded in a distorted bent 120 degrees geometry to two equivalent Cs, one Ca, and one Cl atom. The O–Cl bond length is 1.67 Å. There are two inequivalent Cl sites. In the first Cl site, Cl is bonded in a 2-coordinate geometry to three equivalent Cs, one Ca, and one O atom. In the second Cl site, Cl is bonded in a 5-coordinate geometry to four equivalent Cs and one Ca atom.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Magnetic excitation linking quasi-one-dimensional Chevrel-type selenide and arsenide superconductors

The quasi-one-dimensional Chevrel phases, A 2 M o6 Se 6 (A=Tl, In, K, Rb, Cs), are of interest due to their atypical electronic properties. The Tl and In analogs undergo a superconducting transition whereas the alkali metal analogs show charge gapping of another, not well understood type. Here we report the results of inelastic neutron scattering on polycrystalline In 2 Mo 6 Se 6 (T c =2.85 K) and Rb 2 Mo 6 Se 6 (nonsuperconducting) samples, which reveal a column of intensity with linear dispersion from [0 0 1/2] to [0 0 1] in both compounds. The observed temperature and |Q| independence together suggest the presence of unconventional carriers with a spin contribution to the excitation. This is contrary to the prevailing model for these materials, which is that they are nonmagnetic. The excitation has similar dispersion and S(Q,E,T) behavior as one observed in the structurally related superconducting compounds A 2 Cr 3 As 3 and A 2 Mo 3 As 3 (A=K, Rb, Cs), which has been interpreted as magnetic in origin and related to Fermi surface nesting. The connection is unexpected because the calculated Fermi surface of the arsenides differs substantially from the A 2 Mo 6 Se 6 compounds, and many consider them distinct classes of materials. This observation suggests a hidden link in the physics between both classes of superconductors, perhaps originating from their quasi-low-dimensional character.

1-dimensional systems↗
DOE OSTI2026

Adsorption, charge transfer and a coverage-driven transition of alkali metals on rutile TiO 2 (110)

The interaction of alkali metals with metal oxide surfaces is central to tuning surface reactivity in heterogeneous catalysis and photocatalysis. Here we present a comprehensive DFT+U study of the adsorption of alkali metals (Li, Na, K, Rb, Cs) on the (110) surface of rutile TiO 2 . At low coverage (θ = 1/8), all alkali metals bind preferentially to bridging oxygen sites with adsorption energies in the range −4.06 to −3.33 eV, transferring nearly one full electron (0.92–0.99 |e|) to the substrate and inducing Ti 4+ → Ti 3+ reduction. The excess charge localizes preferentially at subsurface Ti sites in the form of small polarons. Diffusion barriers indicate facile motion along bridging-oxygen rows, whereas inter-row hopping is strongly hindered. Coverage effects were examined systematically for potassium: adsorption energy and charge transfer per K atom decrease monotonically with increasing θ. Strikingly, a sharp energy discontinuity occurs between θ = 4/8 and θ = 5/8 (ΔE ≈ 1 eV per atom), which we identify as a coverage-driven structural transition arising from steric packing constraints and enhanced K–K electrostatic repulsion once every (1×1) surface cell is occupied. This structural transition perfectly correlates with a dramatic drop in the work function down to an ultra-low minimum of 0.84 eV at θ=5/8, followed by a metallization- driven recovery at higher coverages. Ab initio molecular dynamics simulations confirm zigzag K arrangements at moderate coverage (θ = 1/3), while at high coverage (θ = 2/3) short-range K–K correlations emerge without long-range order. These results provide atomistic insight into the structure–activity relationships underlying alkali promotion effects on oxide-supported catalysts.

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

Comparison and investigation of production of specific nuclides by different fission yield data

Generally, passive gamma spectroscopy (PGS) is known as a useful technique for nondestructive measurement of burnup and nuclide production in normal spent nuclear fuel. However, PGS can be used not only for normal spent fuel, but also for molten fuel generated in severe accidents involving core meltdowns. In such cases, it is estimated by the radioactivity ratios of specific nuclides. At the time of the decommissioning of the Three Mile Island's unit 2 reactor, fission products (FPs) such as Cs{sup 134}, Cs{sup 137}, Ce{sup 144}, Eu{sup 154}, Ru{sup 106}, and Sb{sup 125} were concerned. The radioactivity ratios are estimated by numerical simulations. However, there are various uncertainties in numerical simulations. In this study, we evaluated the effect of the difference in fission yield data. We compared the productions of concerned nuclides of Three Mile Island's unit 2 reactor by using Tokyo-tech and JENDL FP Fission Yields Data File 2011(FPY- 2011). Tokyo-tech is newly created by Tsubakihara et al. at Tokyo Institute of Technology. FPY-2011 is currently the latest fission yield data in Japan. In the concerned nuclides, the relative difference (Tokyo-tech/FPY-2011 -1) in the production of Sb{sup 125} is 4.5% and that of Eu{sup 154} is -5.6%. The relative difference in the production of Sb{sup 125} is found to be caused by the difference in the independent yields of Sn{sup 125}, In{sup 125}, Cd{sup 125}, Ag{sup 125}, and Pd{sup 125}. The relative difference in Eu{sup 154} is found to be caused by the relative difference in the production of Sm{sup 152} and the relative difference in the cumulative yield of Eu{sup 153}.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2020

Materials Data on Cs2Nb4O11 by Materials Project

Cs2Nb4O11 crystallizes in the orthorhombic Pnn2 space group. The structure is three-dimensional. there are four inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to seven O2- atoms. There are a spread of Cs–O bond distances ranging from 2.99–3.47 Å. In the second Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cs–O bond distances ranging from 3.19–3.65 Å. In the third Cs1+ site, Cs1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cs–O bond distances ranging from 3.21–3.64 Å. In the fourth Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to seven O2- atoms. There are a spread of Cs–O bond distances ranging from 2.99–3.46 Å. There are nine inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 35–45°. There are a spread of Nb–O bond distances ranging from 1.88–2.17 Å. In the second Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 35–43°. There are a spread of Nb–O bond distances ranging from 1.96–2.05 Å. In the third Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with five NbO6 octahedra and a cornercorner with one NbO4 tetrahedra. The corner-sharing octahedra tilt angles range from 29–45°. There are a spread of Nb–O bond distances ranging from 1.89–2.27 Å. In the fourth Nb5+ site, Nb5+ is bonded to four O2- atoms to form corner-sharing NbO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–62°. There is two shorter (1.86 Å) and two longer (1.91 Å) Nb–O bond length. In the fifth Nb5+ site, Nb5+ is bonded to six O2- atoms to form corner-sharing NbO6 octahedra. The corner-sharing octahedra tilt angles range from 35–45°. There are a spread of Nb–O bond distances ranging from 1.88–2.17 Å. In the sixth Nb5+ site, Nb5+ is bonded to six O2- atoms to form NbO6 octahedra that share corners with five NbO6 octahedra and a cornercorner with one NbO4 tetrahedra. The corner-sharing octahedra tilt angles range from 29–45°. There are a spread of Nb–O bond distances ranging from 1.89–2.28 Å. In the seventh Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share corners with four NbO6 octahedra, corners with two NbO4 tetrahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedra tilt angles range from 29–34°. There are a spread of Nb–O bond distances ranging from 1.88–2.29 Å. In the eighth Nb5+ site, Nb5+ is bonded to four O2- atoms to form corner-sharing NbO4 tetrahedra. The corner-sharing octahedra tilt angles range from 53–62°. There is two shorter (1.86 Å) and two longer (1.91 Å) Nb–O bond length. In the ninth Nb5+ site, Nb5+ is bonded to six O2- atoms to form distorted NbO6 octahedra that share corners with four NbO6 octahedra, corners with two NbO4 tetrahedra, and an edgeedge with one NbO6 octahedra. The corner-sharing octahedra tilt angles range from 29–34°. There are a spread of Nb–O bond distances ranging from 1.87–2.29 Å. There are twenty-two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+ and two Nb5+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Nb5+ atoms. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two Nb5+ atoms. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Cs1+ and two Nb5+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two Nb5+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Nb5+ atoms. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two Nb5+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cs1+ and two Nb5+ atoms. In the ninth O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+ and two Nb5+ atoms. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to one Cs1+ and two Nb5+ atoms. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one Cs1+ and two Nb5+ atoms. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two Nb5+ atoms. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two Nb5+ atoms. In the fourteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+ and two Nb5+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two Nb5+ atoms. In the sixteenth O2- site, O2- is bonded in a 2-coordinate geometry to two Cs1+ and two Nb5+ atoms. In the seventeenth O2- site, O2- is bonded in a 2-coordinate geometry to two Cs1+ and two Nb5+ atoms. In the eighteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+ and two Nb5+ atoms. In the nineteenth O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+ and two Nb5+ atoms. In the twentieth O2- site, O2- is bonded in a 2-coordinate geometry to one Cs1+ and two Nb5+ atoms. In the twenty-first O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two Nb5+ atoms. In the twenty-second O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two Nb5+ atoms.

36 MATERIALS SCIENCE↗