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All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Lifetime measurements in the even-even Cd 102 – 108 isotopes

The heaviest T z = 0 doubly-magic nucleus, Sn 100 , and the neighboring nuclei offer unique opportunities to investigate the properties of nuclear interaction. For instance, the structure of light-Sn nuclei has been shown to be affected by the delicate balance between nuclear-interaction components, such as pairing and quadrupole correlations. From Cd to Te, many common features and phenomena have been observed experimentally along the isotopic chains, leading to theoretical studies devoted to a more general and comprehensive study of the region. In this context, having only two proton holes in the Z = 50 shell, the Cd isotopes are expected to present properties similar to those found in the Sn isotopic chain. The aim of this work was to measure lifetimes of excited states in neutron-deficient nuclei in the vicinity of Sn 100 . Here, the neutron-deficient nuclei in the N ≈ Z ≈ 50 region were populated using a multinucleon transfer reaction with a Cd 106 beam and a Mo 92 target. The beamlike products were identified by the VAMOS + + spectrometer, while the γ rays were detected using the AGATA array. Lifetimes of excited states were determined using the recoil distance Doppler-shift method, employing the Cologne differential plunger. Lifetimes of low-lying states were measured in the even-mass Cd 102 – 108 isotopes. In particular, multiple states with excitation energy up to ≈ 3 MeV, belonging to various bands, were populated in Cd 106 via inelastic scattering. The transition strengths corresponding to the measured lifetimes were compared with those resulting from state-of-the-art beyond-mean-field calculations using the symmetry-conserving configuration-mixing approach. Conclusions: Despite the similarities in the electromagnetic properties of the low-lying states, there is a fundamental structural difference between the ground-state bands in the Z = 48 and Z = 50 isotopes. The comparison between experimental and theoretical results revealed a rotational character of the Cd nuclei, which have prolate-deformed ground states with β 2 ≈ 0.2 . At this deformation Z = 48 becomes a closed-shell configuration, which is favored with respect to the spherical one.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Materials Data on Cd(CoO2)2 by Materials Project

Cd(CoO2)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Co3+ sites. In the first Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and a faceface with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 1.89–2.27 Å. In the second Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and an edgeedge with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 1.89–2.22 Å. In the third Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and a faceface with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 1.90–2.20 Å. In the fourth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with three CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and an edgeedge with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 1.90–2.18 Å. In the fifth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and an edgeedge with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 2.00–2.04 Å. In the sixth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and an edgeedge with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 1.99–2.09 Å. In the seventh Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and an edgeedge with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 1.97–2.09 Å. In the eighth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with two equivalent CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and an edgeedge with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 1.97–2.09 Å. There are four inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cd–O bond distances ranging from 2.32–2.43 Å. In the second Cd2+ site, Cd2+ is bonded to six O2- atoms to form distorted CdO6 pentagonal pyramids that share corners with six CoO6 octahedra, edges with six CoO6 octahedra, and edges with two equivalent CdO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 2–17°. There are a spread of Cd–O bond distances ranging from 2.29–2.50 Å. In the third Cd2+ site, Cd2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cd–O bond distances ranging from 2.30–2.50 Å. In the fourth Cd2+ site, Cd2+ is bonded to six O2- atoms to form distorted CdO6 pentagonal pyramids that share corners with twelve CoO6 octahedra, edges with two equivalent CdO6 pentagonal pyramids, and faces with two CoO6 octahedra. The corner-sharing octahedra tilt angles range from 41–54°. There are a spread of Cd–O bond distances ranging from 2.32–2.42 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form distorted OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the second O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the third O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form distorted OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the fourth O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form distorted OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co3+ and one Cd2+ atom. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co3+ and one Cd2+ atom. In the seventh O2- site, O2- is bonded to three Co3+ and one Cd2+ atom to form distorted OCdCo3 trigonal pyramids that share corners with four OCd2Co3 trigonal bipyramids, corners with three OCdCo3 trigonal pyramids, and edges with four OCd2Co3 trigonal bipyramids. In the eighth O2- site, O2- is bonded to three Co3+ and one Cd2+ atom to form distorted OCdCo3 trigonal pyramids that share corners with four OCd2Co3 trigonal bipyramids, corners with three OCdCo3 trigonal pyramids, and edges with four OCd2Co3 trigonal bipyramids. In the ninth O2- site, O2- is bonded to three Co3+ and one Cd2+ atom to form distorted OCdCo3 trigonal pyramids that share corners with four OCd2Co3 trigonal bipyramids, corners with three OCdCo3 trigonal pyramids, and edges with four OCd2Co3 trigonal bipyramids. In the tenth O2- site, O2- is bonded to three Co3+ and one Cd2+ atom to form distorted OCdCo3 trigonal pyramids that share corners with four OCd2Co3 trigonal bipyramids, corners with three OCdCo3 trigonal pyramids, and edges with four OCd2Co3 trigonal bipyramids. In the eleventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co3+ and one Cd2+ atom. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co3+ and one Cd2+ atom. In the thirteenth O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the fourteenth O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form distorted OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form distorted OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the sixteenth O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd(CoO2)2 by Materials Project

Cd(CoO2)2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are eight inequivalent Co3+ sites. In the first Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with five CdO6 pentagonal pyramids, edges with six CoO6 octahedra, an edgeedge with one CdO6 pentagonal pyramid, and a faceface with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 1.90–2.15 Å. In the second Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with five CdO6 pentagonal pyramids, edges with six CoO6 octahedra, an edgeedge with one CdO6 pentagonal pyramid, and a faceface with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 1.90–2.14 Å. In the third Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with five CdO6 pentagonal pyramids, edges with six CoO6 octahedra, an edgeedge with one CdO6 pentagonal pyramid, and a faceface with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 1.90–2.14 Å. In the fourth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with five CdO6 pentagonal pyramids, edges with six CoO6 octahedra, an edgeedge with one CdO6 pentagonal pyramid, and a faceface with one CdO6 pentagonal pyramid. There are a spread of Co–O bond distances ranging from 1.90–2.15 Å. In the fifth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and edges with two CdO6 pentagonal pyramids. There are a spread of Co–O bond distances ranging from 1.99–2.07 Å. In the sixth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and edges with two CdO6 pentagonal pyramids. There are a spread of Co–O bond distances ranging from 1.99–2.07 Å. In the seventh Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and edges with two CdO6 pentagonal pyramids. There are a spread of Co–O bond distances ranging from 1.99–2.07 Å. In the eighth Co3+ site, Co3+ is bonded to six O2- atoms to form CoO6 octahedra that share corners with four CdO6 pentagonal pyramids, edges with six CoO6 octahedra, and edges with two CdO6 pentagonal pyramids. There are a spread of Co–O bond distances ranging from 1.99–2.07 Å. There are four inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to six O2- atoms to form distorted CdO6 pentagonal pyramids that share corners with twelve CoO6 octahedra, edges with two equivalent CdO6 pentagonal pyramids, and faces with two CoO6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of Cd–O bond distances ranging from 2.34–2.41 Å. In the second Cd2+ site, Cd2+ is bonded to six O2- atoms to form distorted CdO6 pentagonal pyramids that share corners with six CoO6 octahedra, edges with six CoO6 octahedra, and edges with two equivalent CdO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 4–17°. There are a spread of Cd–O bond distances ranging from 2.31–2.41 Å. In the third Cd2+ site, Cd2+ is bonded to six O2- atoms to form distorted CdO6 pentagonal pyramids that share corners with six CoO6 octahedra, edges with six CoO6 octahedra, and edges with two equivalent CdO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 4–18°. There are a spread of Cd–O bond distances ranging from 2.30–2.42 Å. In the fourth Cd2+ site, Cd2+ is bonded to six O2- atoms to form distorted CdO6 pentagonal pyramids that share corners with twelve CoO6 octahedra, edges with two equivalent CdO6 pentagonal pyramids, and faces with two CoO6 octahedra. The corner-sharing octahedra tilt angles range from 44–53°. There are a spread of Cd–O bond distances ranging from 2.34–2.40 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the second O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the third O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the fourth O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co3+ and one Cd2+ atom. In the sixth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co3+ and one Cd2+ atom. In the seventh O2- site, O2- is bonded to three Co3+ and one Cd2+ atom to form OCdCo3 trigonal pyramids that share corners with four OCd2Co3 trigonal bipyramids, corners with three OCdCo3 trigonal pyramids, and edges with four OCd2Co3 trigonal bipyramids. In the eighth O2- site, O2- is bonded to three Co3+ and one Cd2+ atom to form OCdCo3 trigonal pyramids that share corners with four OCd2Co3 trigonal bipyramids, corners with three OCdCo3 trigonal pyramids, and edges with four OCd2Co3 trigonal bipyramids. In the ninth O2- site, O2- is bonded to three Co3+ and one Cd2+ atom to form distorted OCdCo3 trigonal pyramids that share corners with four OCd2Co3 trigonal bipyramids, corners with three OCdCo3 trigonal pyramids, and edges with four OCd2Co3 trigonal bipyramids. In the tenth O2- site, O2- is bonded to three Co3+ and one Cd2+ atom to form OCdCo3 trigonal pyramids that share corners with four OCd2Co3 trigonal bipyramids, corners with three OCdCo3 trigonal pyramids, and edges with four OCd2Co3 trigonal bipyramids. In the eleventh O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co3+ and one Cd2+ atom. In the twelfth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to three Co3+ and one Cd2+ atom. In the thirteenth O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the fourteenth O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the fifteenth O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids. In the sixteenth O2- site, O2- is bonded to three Co3+ and two Cd2+ atoms to form OCd2Co3 trigonal bipyramids that share corners with five OCd2Co3 trigonal bipyramids, corners with two OCdCo3 trigonal pyramids, edges with four OCd2Co3 trigonal bipyramids, and edges with two OCdCo3 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd by Materials Project

Cd is Magnesium structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Cd is bonded to twelve equivalent Cd atoms to form a mixture of corner, edge, and face-sharing CdCd12 cuboctahedra. There are six shorter (3.01 Å) and six longer (3.44 Å) Cd–Cd bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd by Materials Project

Cd is Copper structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Cd is bonded to twelve equivalent Cd atoms to form a mixture of corner, edge, and face-sharing CdCd12 cuboctahedra. There are six shorter (3.11 Å) and six longer (3.29 Å) Cd–Cd bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd by Materials Project

Cd is Copper structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Cd is bonded to twelve equivalent Cd atoms to form a mixture of corner, edge, and face-sharing CdCd12 cuboctahedra. All Cd–Cd bond lengths are 3.20 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Selectivity in gas–liquid interactions: Molecular beam scattering of CD 4 and ND 3 from an aqueous flat liquid jet

The dynamics of polar and nonpolar molecules colliding with an aqueous surface are characterized by scattering molecular beams of deuterated methane and ammonia, CD 4 and ND 3 (E i = 28.9 and 30.3 kJ mol −1 , respectively), from a flat liquid jet of cold salty water (8 m LiBr, 230 K). Translational energy distributions of scattered species collected as a function of collision geometry probe both impulsive scattering (IS) and thermal desorption (TD) mechanisms. Here, we find that CD 4 scattering is dominated by IS and exhibits a super-specular angular distribution. The fraction of TD scattering events is notably smaller for cold salty water than for dodecane, consistent with a higher free energy of solvation for CD 4 in the water jet. In contrast, no scattering signal is seen for ND 3 from the water jet, a result attributed to the high solubility and efficient protonation of ND 3 in liquid water. The IS channel for CD 4 was analyzed using a soft-sphere model, yielding a higher internal energy (E int ) and lower effective surface mass (m eff ) than was seen for Ne/water; the higher value of E int is attributed to rotational excitation of the scattered CD 4 . These findings demonstrate that the outcomes of a gas–liquid collision—scattering trajectory, surface adherence, and energy transfer—are directed at the molecular level by both the gaseous scatterer and liquid surface.

Foreman, Madison M. [University of California, Ber↗
DOE OSTI2022

Challenges to magnetic doping of thin films of the Dirac semimetal Cd 3 As 2

Magnetic doping of topological quantum materials provides an attractive route for studying the effects of time-reversal symmetry breaking. Thus motivated, we explore the introduction of the transition metal Mn into thin films of the Dirac semimetal Cd 3 A s2 during growth by molecular beam epitaxy. Scanning transmission electron microscopy measurements show the formation of a Mn-rich phase at the top surface of Mn-doped Cd 3 A s2 thin films grown using both uniform doping and delta doping. This suggests that Mn acts as a surfactant during epitaxial growth of Cd 3 A s2 , resulting in phase separation. Magnetometry measurements of such samples indicate a ferromagnetic phase with out-of-plane magnetic anisotropy. Electrical magneto-transport measurements of these films as a function of temperature, magnetic field, and chemical potential reveal a lower carrier density and higher electron mobility compared with pristine Cd 3 A s2 films grown under similar conditions. This suggests that the surfactant effect might also serve to remove impurities from the bulk of the film. Further, we observe robust quantum transport (Shubnikov-de Haas oscillations and an incipient integer quantum Hall effect) in very thin (7 nm) Cd 3 A s2 films despite being in direct contact with a structurally disordered surface ferromagnetic overlayer.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd(CN)2 by Materials Project

Cd(CN)2 is Tungsten structured and crystallizes in the cubic P-43m space group. The structure is zero-dimensional and consists of one cadmium molecule and one Cd(CN)4 cluster. In the Cd(CN)4 cluster, Cd2+ is bonded in a tetrahedral geometry to four equivalent N3- atoms. All Cd–N bond lengths are 2.19 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a linear geometry to one Cd2+ and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd(HO)2 by Materials Project

Cd(OH)2 crystallizes in the trigonal P3m1 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 in a distorted q6 geometry to three equivalent H1+ and six O2- atoms. All Cd–H bond lengths are 2.22 Å. There are three shorter (2.39 Å) and three longer (2.43 Å) Cd–O bond lengths. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to three equivalent Cd2+ and one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to three equivalent Cd2+ and one H1+ atom. In the second O2- site, 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(BO2)2 by Materials Project

Cd(BO2)2 crystallizes in the orthorhombic Pna2_1 space group. The structure is three-dimensional. there are three inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Cd–O bond distances ranging from 2.30–2.72 Å. In the second Cd2+ site, Cd2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Cd–O bond distances ranging from 2.27–2.49 Å. In the third Cd2+ site, Cd2+ is bonded in a 2-coordinate geometry to eight O2- atoms. There are a spread of Cd–O bond distances ranging from 2.24–2.82 Å. There are six inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.44 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.35 Å) and two longer (1.39 Å) B–O bond length. In the third B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.56 Å. In the fourth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.45–1.56 Å. In the fifth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.46–1.54 Å. In the sixth B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.46–1.51 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cd2+ and two B3+ atoms. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cd2+ and two B3+ atoms. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two Cd2+ and one B3+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to three Cd2+ and one B3+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two Cd2+ and two B3+ atoms. In the sixth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Cd2+ and two B3+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to one Cd2+ and two B3+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cd2+ and two B3+ atoms. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to one Cd2+ and two B3+ atoms. In the tenth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cd2+ and two B3+ atoms. In the eleventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cd2+ and two B3+ atoms. In the twelfth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cd2+ and two B3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Rice husk and charred husk amendments increase porewater and plant Si but water management determines grain As and Cd concentration

Abstract Purpose Rice is a staple crop worldwide and a silicon (Si) hyperaccumulator with Si levels reaching 5–10% of its mass; this can result in desilication and Si-deficiency if plant residues are not managed correctly. Rice is also uniquely subject to arsenic (As) and cadmium (Cd) contamination depending on soil conditions. Our goal is to quantify the effects of rice husk (a Si-rich milling byproduct) amendments and different water management strategies on rice uptake of Si, As, and Cd. Methods We employed 4 husk amendment treatments: Control (no husk), Husk (untreated husk), Biochar (husk pyrolyzed at 450 °C), and CharSil (husk combusted at > 1000 °C). Each of these amendments was studied under nonflooded, alternate wetting and drying (AWD), and flooded water management in a pot study. Porewater chemistry and mature plant elemental composition were measured. Results Husk and Biochar treatments, along with flooding, increased porewater and plant Si. Vegetative tissue As decreased with increasing porewater Si, but grain As and plant Cd were primarily controlled by water management. Grain As and Cd were inversely correlated and are simultaneously minimized in a redox potential (Eh) range of 225–275 mV in the studied soil. Ferrihydrite in root iron plaque decreased As translocation from porewater to grain, but amendments were not able to increase plaque ferrihydrite content. Conclusion We conclude moderate husk amendment rates (i.e., 4 years’ worth) with minimal pretreatment strongly increases rice Si content but may not be sufficient to decrease grain As in low Si and As soil.

36 MATERIALS SCIENCE↗
DOE OSTI2022

E2 rotational invariants of 0$^{+}_{1}$ and 2$^{+}_{1}$ states for 106 Cd: The emergence of collective rotation

The collective structure of 106 Cd is elucidated by multi-step Coulomb excitation of a 3.849 MeV/A beam of 106 Cd on a 1.1 mg/cm 2 208 Pb target using GRETINA-CHICO2 at ATLAS. Fourteen E2 matrix elements were obtained. The nucleus 106 Cd is a prime example of emergent collectivity that possesses a simple structure: it is free of complexity caused by shape coexistence and has a small, but collectively active number of valence nucleons. This work follows in a long and currently active quest to answer the fundamental question of the origin of nuclear collectivity and deformation, notably in the cadmium isotopes. The results are discussed in terms of phenomenological models, the shell model, and Kumar-Cline sums of E2 matrix elements. The < 0$^{+}_{2}$ ||E2||2$^{+}_{1}$ > matrix element is determined for the first time, providing a total, converged measure of the electric quadrupole strength, < Q 2 >, of the first-excited 2$^{+}_{1}$ level relative to the 0$^{+}_{1}$ ground state, which does not show an increase as expected of harmonic and anharmonic vibrations. Strong evidence for triaxial shapes in weakly collective nuclei is indicated; collective vibrations are excluded. This is contrary to the only other cadmium result of this kind in 114 Cd by C. Fahlander et al., Nucl. Phys. A485, 327 (1988), which is complicated by low-lying shape coexistence near midshell.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2026

Dynamic Nuclear Polarization Enhanced 113 Cd Solid-State Nuclear Magnetic Resonance Spectroscopy Reveals CdSe Nanocrystals with Triangular Two-Dimensional Projections are Terminated by {100} Facets

Surface structure plays an important role in particle growth and determining the chemical and photophysical properties of semiconductor nanocrystals (NCs). Therefore, there is a need for structural tools that can characterize and detect different surface facets. Here, we sought to investigate the structure of {111} CdSe facets by applying dynamic nuclear polarization (DNP) enhanced 113 Cd and 77 Se solid-state nuclear magnetic resonance (SSNMR) spectroscopy to zinc-blende CdSe NCs that exhibit triangular two-dimensional (2D) projections within transmission electron microscope (TEM) images. It was originally hypothesized in the literature that these CdSe NCs were tetrahedral in shape and terminated by facets from the {111} family of lattice planes of the zinc-blende structure. Surprisingly, we observe 113 Cd NMR spectra indicating that the primary facets are from the {100} family of lattice planes. We also obtained DNP-enhanced 113 Cd and 77 Se SSNMR spectra of recently reported right trigonal bipyramidal (rTriBP) CdSe NCs grown by seeded growth. The 113 Cd NMR spectra rTriBP CdSe NCs are consistent with {100} surface facets. TEM images show that rTriBP NCs may also exhibit triangular 2D projections that are similar to the so-called tetrahedral NCs. Based upon these results, we conclude that the so-called tetrahedral NCs are predominantly terminated by {100} surface facets and most likely have the same shape as rTriBP NCs. These results highlight the need for multiple complementary techniques when assigning the shape and surface termination of NCs.

Santhiran, Anuluxan [Ames Laboratory (AMES), Ames,↗
DOE OSTI2022

20%-efficient polycrystalline Cd(Se,Te) thin-film solar cells with compositional gradient near the front junction

Bandgap gradient is a proven approach for improving the open-circuit voltages (V OC s) in Cu(In,Ga)Se 2 and Cu(Zn,Sn)Se 2 thin-film solar cells, but has not been realized in Cd(Se,Te) thin-film solar cells, a leading thin-film solar cell technology in the photovoltaic market. Here, we demonstrate the realization of a bandgap gradient in Cd(Se,Te) thin-film solar cells by introducing a Cd(O,S,Se,Te) region with the same crystal structure of the absorber near the front junction. The formation of such a region is enabled by incorporating oxygenated CdS and CdSe layers. We show that the introduction of the bandgap gradient reduces the hole density in the front junction region and introduces a small spike in the band alignment between this and the absorber regions, effectively suppressing the nonradiative recombination therein and leading to improved VOCs in Cd(Se,Te) solar cells using commercial SnO 2 buffers. A champion device achieves an efficiency of 20.03% with a V OC of 0.863 V.

14 SOLAR ENERGY↗
DOE OSTI2023

Vacancy complexes in Cd 3 As 2

Epitaxial growth of the three-dimensional topological semimetal Cd 3 As 2 on semiconductor substrates enables its use and integration in device applications. Epitaxy also provides an avenue for varying and controlling point defects through modification of the chemical potential during growth. In turn, knowledge of the point defects that are generated in Cd 3 As 2 epilayers will aid the interpretation of electron transport behavior and guide growth efforts to produce material with low defect densities. Point defects in Cd 3 As 2 epilayers grown by molecular beam epitaxy with varying As/Cd flux ratios are probed by positron annihilation spectroscopy. We find that lower As/Cd flux ratios produce higher concentrations of point defects. Remarkably, the measurements indicate that the average defect size is larger than a monovacancy. The data presented here contribute to an evolving picture of vacancy point defects in Cd 3 As 2 and can be used to direct future investigation of the defect-transport relationships in this emerging electronic material.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Band Energy Dependence of Defect Formation in the Topological Semimetal Cd3As2

Cadmium Arsenide (Cd3As2) is a prototypical Dirac semimetal that manifests topological properties in a 3D bulk material. In defect-free Cd3As2, the Fermi level lies at a minimum in the density of states at the Dirac point, but experimentally it forms with excess electron carriers and an elevated EF, thereby masking the topological features. To computationally study the self-doping of Cd3As2, we combine density functional theory (DFT) calculations for defect formation energies with quasi-particle self-consistent GW (QSGW) electronic structure calculations. We demonstrate an innate dependence of the point defect formation energies on carrier concentrations and use the QSGW calculated density of states to extrapolate formation energies to arbitrary electron concentrations. This approach allows the quantitative modeling of thermodynamic defect equilibria in topological semimetals and is used to predict how Cd3As2 growth conditions affect the position of EF relative to the Dirac point.

CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS↗
DOE OSTI2021

Exploring the role of high- j configurations in collective observables through the Coulomb excitation of 106 Cd

In this work, the shape and collectivity of 106 Cd was investigated via a sub-barrier-energy Coulomb excitation experiment performed at the NSCL ReA3 facility using the JANUS setup. Transition matrix elements between low-lying states were found to agree with adopted values, and information on the shape and collectivity of higher-lying states was extracted for the first time. Locally-optimized large-scale shell-model calculations were found to describe well the B(E2) transition strengths but failed to reproduce the spectroscopic quadrupole moments Q s . An analysis of the E2 rotational invariants and the normalized quadrupole moment q s indicates that this may be due to a significant degree of triaxiality in 106 Cd which is not captured by the present shell-model calculations. Analogous calculations for the Fe isotopes (two protons below the Z = 28 magic number) reveal the critical role of high-j neutron configurations for the description of quadrupole moments in the heavy Fe and Cd isotopes (two protons below magic Z = 50), but this effect is insufficient to explain the shape of 106 Cd, posing a puzzle for the understanding of nuclear structure towards N = 50.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗