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DOE OSTI2020

Materials Data on Cd(HO)2 by Materials Project

Cd(OH)2 crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Cd(OH)2 sheet oriented in the (0, 0, 1) direction. Cd2+ is bonded to six equivalent O2- atoms to form edge-sharing CdO6 octahedra. All Cd–O bond lengths are 2.35 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. O2- is bonded in a single-bond geometry to three equivalent Cd2+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd(HO)2 by Materials Project

Cd(OH)2 crystallizes in the monoclinic C2 space group. The structure is two-dimensional and consists of one Cd(OH)2 sheet oriented in the (0, 0, 1) direction. Cd2+ is bonded to six equivalent O2- atoms to form edge-sharing CdO6 octahedra. There are a spread of Cd–O bond distances ranging from 2.31–2.39 Å. H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. O2- is bonded in a distorted single-bond geometry to three equivalent Cd2+ and one H1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd(Bi9O14)2 by Materials Project

CdCd(Bi9O14)4 is Antimony trioxide-derived structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional and consists of one cadmium molecule and one Cd(Bi9O14)4 framework. In the Cd(Bi9O14)4 framework, Cd2+ is bonded in a bent 150 degrees geometry to two O2- atoms. There are one shorter (2.68 Å) and one longer (2.75 Å) Cd–O bond lengths. There are thirty-six inequivalent Bi3+ sites. In the first Bi3+ site, Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.20–2.89 Å. In the second Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.17–2.71 Å. In the third Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.09–2.89 Å. In the fourth Bi3+ site, Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.20–2.72 Å. In the fifth Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.14–2.73 Å. In the sixth Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.15–2.93 Å. In the seventh Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.14–3.03 Å. In the eighth Bi3+ site, Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.22–2.85 Å. In the ninth Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.18–2.85 Å. In the tenth Bi3+ site, Bi3+ is bonded to five O2- atoms to form distorted corner-sharing BiO5 square pyramids. There are a spread of Bi–O bond distances ranging from 2.10–2.68 Å. In the eleventh Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.15–2.85 Å. In the twelfth Bi3+ site, Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.18–3.01 Å. In the thirteenth Bi3+ site, Bi3+ is bonded to five O2- atoms to form distorted corner-sharing BiO5 square pyramids. There are a spread of Bi–O bond distances ranging from 2.16–2.40 Å. In the fourteenth Bi3+ site, Bi3+ is bonded in a distorted square pyramidal geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.16–2.48 Å. In the fifteenth Bi3+ site, Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.23–2.83 Å. In the sixteenth Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.16–2.69 Å. In the seventeenth Bi3+ site, Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.21–2.92 Å. In the eighteenth Bi3+ site, Bi3+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Bi–O bond distances ranging from 2.24–2.40 Å. In the nineteenth Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.17–2.71 Å. In the twentieth Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.17–2.71 Å. In the twenty-first Bi3+ site, Bi3+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.11–2.51 Å. In the twenty-second Bi3+ site, Bi3+ is bonded in a distorted pentagonal planar geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.25–2.45 Å. In the twenty-third Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.14–2.46 Å. In the twenty-fourth Bi3+ site, Bi3+ is bonded in a distorted T-shaped geometry to three O2- atoms. There are a spread of Bi–O bond distances ranging from 2.21–2.50 Å. In the twenty-fifth Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.21–2.34 Å. In the twenty-sixth Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.14–2.96 Å. In the twenty-seventh Bi3+ site, Bi3+ is bonded in a distorted square pyramidal geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.18–2.58 Å. In the twenty-eighth Bi3+ site, Bi3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Bi–O bond distances ranging from 2.19–2.74 Å. In the twenty-ninth Bi3+ site, Bi3+ is bonded in a distorted see-saw-like geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.14–2.67 Å. In the thirtieth Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.16–2.86 Å. In the thirty-first Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.17–2.96 Å. In the thirty-second Bi3+ site, Bi3+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.17–2.78 Å. In the thirty-third Bi3+ site, Bi3+ is bonded in a 6-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.19–2.98 Å. In the thirty-fourth Bi3+ site, Bi3+ is bonded in a distorted rectangular see-saw-like geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.10–2.91 Å. In the thirty-fifth Bi3+ site, Bi3+ is bonded in a 4-coordinate geometry to four O2- atoms. There are a spread of Bi–O bond distances ranging from 2.12–2.74 Å. In the thirty-sixth Bi3+ site, Bi3+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. All Bi–O bond lengths are 2.12 Å. There are fifty-six inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to four Bi3+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three Bi3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the fifth O2- site, O2- is bonded in a distorted T-shaped geometry to three Bi3+ atoms. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to two Bi3+ atoms. In the seventh O2- site, O2- is bonded in a 7-coordinate geometry to five Bi3+ and two O2- atoms. There are one shorter (1.51 Å) and one longer (2.55 Å) O–O bond lengths. In the eighth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to three Bi3+ and one O2- atom. The O–O bond length is 1.48 Å. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to four Bi3+ atoms. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to three Bi3+ and one O2- atom. The O–O bond length is 1.48 Å. In the twelfth O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to four Bi3+ atoms. In the thirteenth O2- site, O2- is bonded in a trigonal non-coplanar geometry to three Bi3+ atoms. In the fourteenth O2- site, O2- is bonded in a 3-coordinate geometry to two Bi3+ and one O2- atom. In the fifteenth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Bi3+ atoms. In the sixteenth O2- site, O2- is bonded in a 4-coordinate geometry to four Bi3+ atoms. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to four Bi3+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the nineteenth O2- site, O2- is bonded in a 4-coordinate geometry to four Bi3+ atoms. In the twentieth O2- site, O2- is bonded in a 4-coordinate geometry to four Bi3+ atoms. In the twenty-first O2- site, O2- is bonded to one Cd2+ and three Bi3+ atoms to form distorted corner-sharing OCdBi3 trigonal pyramids. In the twenty-second O2- site, O2- is bonded in a 3-coordinate geometry to three Bi3+ atoms. In the twenty-third O2- site, O2- is bonded in a trigonal planar geometry to three Bi3+ and one O2- atom. In the twenty-fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Bi3+ and one O2- atom. In the twenty-fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Bi3+ atoms. In the twenty-sixth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the twenty-seventh O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the twenty-eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Bi3+ atoms. In the twenty-ninth O2- site, O2- is bonded in a distorted trigonal planar geometry to three Bi3+ atoms. In the thirtieth O2- site, O2- is bonded in a 2-coordinate geometry to three Bi3+ atoms. In the thirty-first O2- site, O2- is bonded in a 2-coordinate geometry to four Bi3+ atoms. In the thirty-second O2- site, O2- is bonded in a 4-coordinate geometry to four Bi3+ atoms. In the thirty-third O2- site, O2- is bonded in a distorted trigonal planar geometry to three Bi3+ atoms. In the thirty-fourth O2- site, O2- is bonded in a 2-coordinate geometry to four Bi3+ atoms. In the thirty-fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the thirty-sixth O2- site, O2- is bonded to four Bi3+ atoms to form distorted corner-sharing OBi4 tetrahedra. In the thirty-seventh O2- site, O2- is bonded in a 2-coordinate geometry to two Bi3+ and one O2- atom. In the thirty-eighth O2- site, O2- is bonded in a 3-coordinate geometry to three Bi3+ atoms. In the thirty-ninth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the fortieth O2- site, O2- is bonded in a 3-coordinate geometry to three Bi3+ atoms. In the forty-first O2- site, O2- is bonded in a 3-coordinate geometry to three Bi3+ atoms. In the forty-second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the forty-third O2- site, O2- is bonded in a distorted trigonal planar geometry to three Bi3+ atoms. In the forty-fourth O2- site, O2- is bonded in a distorted T-shaped geometry to three Bi3+ atoms. In the forty-fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to one Cd2+ and two Bi3+ atoms. In the forty-sixth O2- site, O2- is bonded in a 2-coordinate geometry to three Bi3+ atoms. In the forty-seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three Bi3+ atoms. In the forty-eighth O2- site, O2- is bonded in a 3-coordinate geometry to three Bi3+ atoms. In the forty-ninth O2- site, O2- is bonded in a 4-coordinate geometry to four Bi3+ atoms. In the fiftieth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the fifty-first O2- site, O2- is bonded in a 3-coordinate geometry to two Bi3+ and one O2- atom. The O–O bond length is 1.49 Å. In the fifty-second O2- site, O2- is bonded in a trigonal planar geometry to three Bi3+ atoms. In the fifty-third O2- site, O2- is bonded in a 3-coordinate geometry to three Bi3+ atoms. In the fifty-fourth O2- site, O2- is bonded in a distorted tetrahedral geometry to three Bi3+ and one O2- atom. In the fifty-fifth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to three Bi3+ atoms. In the fifty-sixth O2- site, O2- is bonded in a 3-coordinate geometry to th

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd(PO3)2 by Materials Project

Cd(PO3)2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to six O2- atoms to form CdO6 octahedra that share corners with six PO4 tetrahedra and edges with two equivalent CdO6 octahedra. There are a spread of Cd–O bond distances ranging from 2.23–2.42 Å. In the second Cd2+ site, Cd2+ is bonded to six O2- atoms to form CdO6 octahedra that share corners with six PO4 tetrahedra and edges with two equivalent CdO6 octahedra. There are a spread of Cd–O bond distances ranging from 2.26–2.32 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CdO6 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 31–58°. There are a spread of P–O bond distances ranging from 1.48–1.62 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with three CdO6 octahedra and corners with two equivalent PO4 tetrahedra. The corner-sharing octahedra tilt angles range from 18–60°. There are a spread of P–O bond distances ranging from 1.48–1.61 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two P5+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to one Cd2+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Cd2+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Cd2+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two Cd2+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd(GaCl4)2 by Materials Project

Cd(GaCl4)2 crystallizes in the monoclinic Pc space group. The structure is two-dimensional and consists of one Cd(GaCl4)2 sheet oriented in the (0, 1, 0) direction. Cd2+ is bonded to six Cl1- atoms to form CdCl6 octahedra that share corners with two GaCl4 tetrahedra and edges with two GaCl4 tetrahedra. There are a spread of Cd–Cl bond distances ranging from 2.65–2.75 Å. There are two inequivalent Ga3+ sites. In the first Ga3+ site, Ga3+ is bonded to four Cl1- atoms to form GaCl4 tetrahedra that share a cornercorner with one CdCl6 octahedra and an edgeedge with one CdCl6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are a spread of Ga–Cl bond distances ranging from 2.14–2.26 Å. In the second Ga3+ site, Ga3+ is bonded to four Cl1- atoms to form GaCl4 tetrahedra that share a cornercorner with one CdCl6 octahedra and an edgeedge with one CdCl6 octahedra. The corner-sharing octahedral tilt angles are 59°. There are a spread of Ga–Cl bond distances ranging from 2.14–2.26 Å. There are eight inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+ atom. In the second Cl1- site, Cl1- is bonded in an L-shaped geometry to one Cd2+ and one Ga3+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Ga3+ atom. In the fourth Cl1- site, Cl1- is bonded in a bent 120 degrees geometry to one Cd2+ and one Ga3+ atom. In the fifth Cl1- site, Cl1- is bonded in an L-shaped geometry to one Cd2+ and one Ga3+ atom. In the sixth Cl1- site, Cl1- is bonded in a bent 120 degrees geometry to one Cd2+ and one Ga3+ atom. In the seventh Cl1- site, Cl1- is bonded in an L-shaped geometry to one Cd2+ and one Ga3+ atom. In the eighth Cl1- site, Cl1- is bonded in an L-shaped geometry to one Cd2+ and one Ga3+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS1995

Results of CD-R Media Studies

CD-R may become an excellent way to archive because it has a storage life of about 100 years; however , its recorders, test devices and compatibility with CD-ROM readers need to be verified. Of the 250 sample recordings, every byte was retrievable on some CD-ROM readers.

CD-R archiving storage life CD-ROM readers retriev↗
DOE OSTI2023

Prediction of alkaline earth metal ion adsorption on goethite for various background electrolytes with the CD-MUSIC model

As water scarcity drives the use of more saline water sources, contaminant fate and transport models must capture the impact of high concentrations of alkaline earth metal ions (AEMs) and background electrolytes in these more complex waters. By utilizing macroscopic adsorption data from various electrolyte systems, a Charge Distribution – Multisite Complexation (CD-MUSIC) model, capable of incorporating electrolyte adsorption, was able to accurately simulate the adsorption behavior of alkaline earth metal ions onto goethite. The modeling effort was guided by previous spectroscopic and surface complexation modeling of alkaline earth metal adsorption and built on previous CD-MUSIC modeling that accounted for changes in crystal face contributions to the surface site density as a function of specific surface area. Further, the model was constrained to consider only two dominant surface complex species for each metal ion adsorption reaction. These two species were selected from 44 possible species through objective curve fitting of single-solute macroscopic adsorption data. While most of the alkaline earth metal surface complexes formed outer-sphere complexes at the goethite surface, an inner-sphere species was utilized for Mg 2+ . With the surface complex species and equilibrium constants obtained from this study, the calibrated model successfully predicted alkaline earth metal ion adsorption over a wide range of solution and surface conditions; the model predictions encompassed a wide range of pH (5–11), solute/solid ratio (1.37 × 10 -5 – 8.33 × 10 -4 mol -solute /g -solid ), ionic strengths (0.01 M – 0.7 M), and background electrolytes (Na + , Cs + , Rb + , Cl - , and NO 3 - ) using the same crystal face contribution methodology for site density, capacitance values, and surface acidity constants adopted for proton and cadmium adsorption in previous work (Han and Katz, 2019). Model simulations for a range of background water chemistries demonstrated the potential for Mg 2+ to reduce Cd 2+ adsorption to goethite in model seawater and oil- and gas-produced waters.

42 ENGINEERING↗
DOE OSTI2023

Simulating Sea-Ice Deformation in Viscous-Plastic Sea-Ice Models With CD-Grids

Linear kinematic features (LKFs) are found everywhere in the Arctic sea-ice cover. They are strongly localized deformations often associated with the formation of leads and pressure ridges. In viscous-plastic (VP) sea-ice models, the simulation of LKFs depends on several factors such as the grid resolution, the numerical solver convergence, and the placement of the variables on the mesh. In this study, we compare two recently proposed discretization with a CD-grid placement with respect to their ability to reproduce LKFs. The first (CD1) is based on a nonconforming finite element discretization, whereas the second (CD2) uses a conforming subgrid discretization. To analyze their resolution properties, we evaluate runs from different models (e.g., FESOM, MPAS) on a benchmark problem using quadrilateral, hexagonal and triangular meshes. Our findings show that the CD1 setup simulates more deformation structure than the CD2 setup. This highlights the importance of the type of spatial discretization for the simulation of LKFs. Due to the higher number of degrees of freedom, both CD-grids resolve more LKFs than traditional A, B, and C-grids at fixed mesh level. This is an advantage of the CD-grid approach, as high spatial mesh resolution is needed in VP sea-ice models to simulate LKFs.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Electro-physical properties of surface-barrier diodes on low-resistance n-Cd 0.96 Mn 0.04 Te 0.96 Se 0.04 crystals

The electro-physical properties of Cd 0.96 Mn 0.04 Te 0.96 Se 0.04 n-type conductivity single crystals with relatively low resistivity were studied. The determined resistivity of semiconductor single crystals Cd 0.96 Mn 0.04 Te 0.96 Se 0.04 n-type conductivity is equal to ρ≈2 Ω-cm at 293K. The activation energy of dark conductivity, measured from the temperature dependence of the resistivity of the In/Cd 0.96 Mn 0.04 Te 0.96 Se 0.04 /In structure, is equal to ΔE≈0.11eV. From optical measurements of the absorption coefficient from the energy of photons in the region of large α, the band-gap width of the single crystal was found, which is equal to E g =1.53eV. Diode structures of Ni/Cd 0.96 Mn 0.04 Te 0.96 Se 0.04 /In obtained by vacuum sputtering of Ni on the surface of a single crystal n-Cd 0.96 Mn 0.04 Te 0.96 Se 0.04 were manufactured and studied. Here, the rectification coefficient at a voltage of U=1V is equal to 10 8 . Within the framework of the Sah-Noys-Shockley carrier generation-recombination model, a quantitative match of the experimental measurements of the volt-ampere characteristics with the calculation was achieved.

(Cd,Mn)(Te,Se)↗
DOE OSTI2020

Widely Tunable Optical and Thermal Properties of Dirac Semimetal Cd 3 As 2

In this paper, a detailed analysis of the temperature-dependent optical properties of epitaxially grown cadmium arsenide (Cd 3 As 2 ), a newly discovered 3D Dirac semimetal is reported. Fermi level tuning—instigated from Pauli-blocking in the linear Dirac cone—and varying Drude response, generate large variations in the mid- and far-infrared optical properties. Thermo-optic shifts larger than those of traditional III–V semiconductors are demonstrated. Electron scattering rate, plasma frequency edge, Fermi level shift, optical conductivity, and electron effective mass analysis of Cd 3 As 2 thin-films are quantified and discussed in detail. The ab initio density functional study and experimental analysis of epitaxially grown Cd 3 As 2 promise applications for nanophotonic and nanoelectronic devices, such as reconfigurable metamaterials and metasurfaces, nanoscale thermal emitters, and on-chip directional antennas.

36 MATERIALS SCIENCE↗
DOE OSTI2020

σ-Aromaticity-Induced Stabilization of Heterometallic Supertetrahedral Clusters [Zn 6 Ge 16 ] 4– and [Cd 6 Ge 16 ] 4–

Here, the largest heterometallic supertetrahedral clusters, [Zn 6 Ge 16 ] 4– and [Cd 6 Ge 16 ] 4– , were directly self-assembled through highly-charged [Ge 4 ] 4– units and transition metal cations, in which 3-center–2-electron σ bonding in Ge 2 Zn or Ge 2 Cd triangles plays a vital role in the stabilization of the whole structure. The cluster structures have an open framework with a large central cavity of diameter 4.6 Å for Zn and 5.0 Å for Cd, respectively. Time-dependent HRESI-MS spectra show that the larger clusters grow from smaller components with a single [Ge 4 ] 4– and ZnMes 2 units. Calculations performed at the DFT level indicate a very large HOMO–LUMO energy gap in [M 6 Ge 16 ] 4– (2.22 eV), suggesting high kinetic stability that may offer opportunities in materials science. These observations offer a new strategy for the assembly of heterometallic clusters with high symmetry.

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

σ‐Aromaticity‐Induced Stabilization of Heterometallic Supertetrahedral Clusters [Zn 6 Ge 16 ] 4− and [Cd 6 Ge 16 ] 4−

Abstract In this work, the largest heterometallic supertetrahedral clusters, [Zn 6 Ge 16 ] 4− and [Cd 6 Ge 16 ] 4− , were directly self‐assembled through highly‐charged [Ge 4 ] 4− units and transition metal cations, in which 3‐center–2‐electron σ bonding in Ge 2 Zn or Ge 2 Cd triangles plays a vital role in the stabilization of the whole structure. The cluster structures have an open framework with a large central cavity of diameter 4.6 Å for Zn and 5.0 Å for Cd, respectively. Time‐dependent HRESI‐MS spectra show that the larger clusters grow from smaller components with a single [Ge 4 ] 4− and ZnMes 2 units. Calculations performed at the DFT level indicate a very large HOMO–LUMO energy gap in [M 6 Ge 16 ] 4− (2.22 eV), suggesting high kinetic stability that may offer opportunities in materials science. These observations offer a new strategy for the assembly of heterometallic clusters with high symmetry.

Xu, Hong‐Lei↗
DOE OSTI2025

Bridging Experiment and Theory to Reveal Compounds in K–Zn(Cd)–Bi Systems

This study investigates the facile hydride synthesis method guided by theoretical predictions to explore the K–T–Bi (T = Zn, Cd) phase spaces. Using an adaptive genetic algorithm (AGA) and density functional theory (DFT), candidate compositions are identified for experimental validation via a facile hydrides route, permitting experimental screening of K–Zn–Bi and “empty” K–Cd–Bi systems. The previously reported KZnBi and KZn 2 Bi 2 are synthesized alongside newly discovered KCdBi and KCd 2 Bi 2 . While the AGA and DFT predict the stability of these compounds, structural predictions align with the experiment only for KZnBi and KZn 2 Bi 2 . Single-crystal X-ray structure refinements confirm that KZnBi and KZn 2 Bi 2 adopt the hexagonal ZrBeSi- and tetragonal ThCr 2 Si 2 -structure types, respectively. KCdBi has tetragonal PbClF-structure type and KCd 2 Bi 2 belongs to the ThCr 2 Si 2 -structure type. A trend based on the ratio of the metal ionic radii allows to rationalize variation in the structure types within the ATBi family (A = Li–Cs), correctly identifying KCdBi as isostructural to NaZnBi. Thermal stability studied by high-temperature powder X-ray diffraction reveals that Zn-containing compounds melt at higher temperatures (821 K for KZn 2 Bi 2 ) than Cd-containing KCd 2 Bi 2 (635 K). This study highlights the efficacy of combining rapid synthesis techniques with predictive modeling, though structural predictions show some limitations in accuracy.

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

Spectroscopic characterization of Mn 2+ and Cd 2+ coordination to phosphorothioates in the conserved A9 metal site of the hammerhead ribozyme

Phosphorothioate modifications have widespread use in the field of nucleic acids. As substitution of sulfur for oxygen can alter metal coordination preferences, the phosphorothioate metal-rescue experiment is a powerful method for identifying metal coordination sites that influence specific properties in a large RNAs. The A9/G10.1 metal binding site of the hammerhead ribozyme (HHRz) has previously been shown to be functionally important through phosphorothioate rescue experiments. While an A9-S Rp substitution is inhibitory in Mg 2+ , thiophilic Cd 2+ rescues HHRz activity. Mn 2+ is also often used in phosphorothioate metal-rescue studies but does not support activity for the A9-S Rp HHRz. Here, we use EPR, electron spin-echo envelope modulation (ESEEM), and X-ray absorption spectroscopic methods to directly probe the structural consequences of Mn 2+ and Cd 2+ coordination to R p and S p phosphorothioate modifications at the A9/G10.1 site in the truncated hammerhead ribozyme (tHHRz). The results demonstrate that while Cd 2+ does indeed bind to S in the thio-substituted ligand, Mn 2+ coordinates to the non–sulfur oxo group of this phosphorothioate, regardless of isomer. Computational models demonstrate the energetic preference of Mn—O over Mn—S coordination in metal-dimethylthiophosphate models. In the case of the tHHRz, the resulting Mn 2+ coordination preference of oxygen in either R p or S p A9 phosphorothioates differentially tunes catalytic activity, with Mn—O coordination in the A9-S Rp phosphorothioate enzyme being inhibitory.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Exploring the Structure and Performance of Cd–Chalcogenide Photocatalysts in Selective Trifluoromethylation

The field of heterogeneous photoredox catalysis has grown substantially and impacted organic synthesis because of the affordability and reusability of catalysts. This study reports radical trifluoromethylation with Cd–chalcogenide semiconductors. Cd semiconductors, particularly CdSe, are readily available, commercial, visible-light-responsive, heterogeneous photocatalysts. The potential of readily available Cd semiconductors, particularly CdSe, is confirmed by their increased photocatalytic activity toward trifluoromethylation with various substrates, such as (hetero)arenes and vinylic amides/acids, via addition, cyclization, and decarboxylation under visible light. Additionally, the economic significance of this strategy is also highlighted through the scalable synthesis of biologically active molecules followed by catalyst reuse. Moreover, these catalysts are relatively inexpensive compared with transition metal-based homogeneous photocatalysts, presently used in organic synthesis.

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

Concentrations and Health Implications of As, Hg, and Cd and Micronutrients in Rice and Emissions of CH 4 From Variably Flooded Paddies

Abstract The flooded soil conditions under which rice is typically grown are beneficial for boosting yield and decreasing herbicide inputs but may pose a food safety and environmental health risk. Flooded soils lead to reducing conditions and anaerobic metabolisms of soil microorganisms, which mobilizes arsenic from soil into soil solution, where it can be absorbed by rice roots and transported to grain. These conditions also promote the production and emission of methane (CH 4 )—a potent greenhouse gas. To evaluate how water management affects metal(loid) grain concentrations and CH 4 emissions, we conducted a 2‐year field study in which rice paddy water was managed under a range of soil redox conditions that spanned from flooded to non‐flooded. We observed that growing rice under less flooded conditions decreased CH 4 emissions and concentrations of grain total As, grain inorganic As, grain total Hg, and grain inorganic Hg relative to flooded conditions, with more reductions observed as conditions were drier; grain organic As and Hg (MeHg) species also decreased with drier conditions particularly in Year 1. However, the driest conditions tested led to a 50%–97% increase in grain Cd concentrations that exceeded the CODEX limit and grain yield reductions as high as 25% and 40% in Year 1 and 2, respectively. While concentrations of toxic metal(loid)s could be manipulated by water management, micronutrient concentrations were similar or decreased with drier conditions, potentially increasing grain Cd bioaccessibility to humans. Because practices for rice water management are gaining momentum, more research should monitor grain Cd levels along with micronutrients.

Environmental Sciences & Ecology↗
DOE OSTI2025

Pseudo-equilibrium theory for extrinsic doping control of the topological semimetal Cd 3 As 2

The standard approach for predicting defect equilibria from first principles assumes that the solid-state system is initially in a thermodynamic equilibrium with the external atomic reservoirs. This “growth step” is then often followed by a temperature quench in a “pseudo-equilibrium” in which some or all defect concentrations are frozen in until only the Fermi level E F remains to be equilibrated. However, this protocol does not account for the possibility of site exchanges which can create important defect redistributions as long as short-range defect migration is kinetically permissible. To model this redistribution, we developed an approach to solve for the non-equilibrium chemical potentials as a function of temperature while maintaining the overall defect stoichiometry. We then apply this approach to the Dirac semimetal Cd 3 As 2 to model extrinsic doping with group 1/11 and 14 elements. Undoped Cd 3 As 2 exhibits an undesirable mismatch between E F and the Dirac point. This unintentional electron doping originates from intrinsic defects and is difficult to overcome through adjustment of synthesis conditions alone. Employing our pseudo-equilibrium modeling, we identify extrinsic doping strategies for realizing doping-balanced Cd 3 As 2 at the relatively low temperatures accessible in thin-film growth of this material.

36 MATERIALS SCIENCE↗
DOE OSTI2021

The achievement of the T e,div feedback control by CD 4 seeding on EAST

A multi-function divertor feedback control system has been built on Experimental Advanced Superconducting Tokamak (EAST) to treat the divertor heat load issue. With the real-time data of the Langmuir probes and the impurity seeding, the divertor electron temperature (T e,div ) is well controlled to achieve the partial detachment phase. The first trial of the CD 4 seeding for the T e,div reduction has been achieved on EAST long-pulse discharge. In the seeding phase, the T e,div was maintained close to 5 eV, and the surface temperature of the target plate (T surface,div ) had a reduction of about 150° C. The plasma stored energy had a reduction in the control phase, so it is necessary to find a way to keep the good plasma confinement in the next step. The CD 4 injection also mitigated the low hybrid wave coupling rate in some degree. The big volume of the CD 4 injection lifted the Greenwald density fraction from ~0.4 to ~0.7, which made the SOL into high recycling state. As a result, most of the injected carbon particles were in the high ionized state, and with the lower of the T e,div , the tungsten line emission was suppressed obviously.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗