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At least 1,225 records · Page 68
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Charge Radius of the Short-Lived Ni 68 and Correlation with the Dipole Polarizability

We present the first laser spectroscopic measurement of the neutron-rich nucleus 68 Ni at the N = 40 subshell closure and extract its nuclear charge radius. Since this is the only short-lived isotope for which the dipole polarizability $α$ D has been measured, the combination of these observables provides a benchmark for nuclear structure theory. We compare them to novel coupled-cluster calculations based on different chiral two- and three-nucleon interactions, for which a strong correlation between the charge radius and dipole polarizability is observed, similar to the stable nucleus 48 Ca. Three-particle–three-hole correlations in coupled-cluster theory substantially improve the description of the experimental data, which allows to constrain the neutron radius and neutron skin of 68 Ni.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

Materials Data on Al3Bi5Cl12 by Materials Project

(Bi)5(AlCl4)3 is Iron carbide-derived structured and crystallizes in the trigonal R-3c space group. The structure is zero-dimensional and consists of eighteen AlCl4 clusters and six Bi clusters. In each AlCl4 cluster, Al is bonded in a tetrahedral geometry to four Cl atoms. There are two shorter (2.15 Å) and two longer (2.18 Å) Al–Cl bond lengths. There are two inequivalent Cl sites. In the first Cl site, Cl is bonded in a single-bond geometry to one Al atom. In the second Cl site, Cl is bonded in a single-bond geometry to one Al atom. In each Bi cluster, there are two inequivalent Bi sites. In the first Bi site, Bi is bonded in a 2-coordinate geometry to two equivalent Bi atoms. Both Bi–Bi bond lengths are 3.06 Å. In the second Bi site, Bi is bonded in a 6-coordinate geometry to three equivalent Bi atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2NaO2 by Materials Project

K2NaO2 crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one K2NaO2 cluster. K is bonded in a single-bond geometry to one O atom. The K–O bond length is 2.32 Å. Na is bonded in a linear geometry to two equivalent O atoms. Both Na–O bond lengths are 2.18 Å. O is bonded in a linear geometry to one K and one Na atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2MgSb2 by Materials Project

Na2MgSb2 is alpha Niobium phosphide-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one Na2MgSb2 cluster. Na1+ is bonded in a single-bond geometry to one Sb2- atom. The Na–Sb bond length is 2.98 Å. Mg2+ is bonded in a linear geometry to two equivalent Sb2- atoms. Both Mg–Sb bond lengths are 2.69 Å. Sb2- is bonded in a linear geometry to one Na1+ and one Mg2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Yb2I2O by Materials Project

Yb2OI2 is alpha Niobium phosphide-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one Yb2OI2 cluster. Yb2+ is bonded in a linear geometry to one O2- and one I1- atom. The Yb–O bond length is 2.04 Å. The Yb–I bond length is 2.88 Å. O2- is bonded in a linear geometry to two equivalent Yb2+ atoms. I1- is bonded in a single-bond geometry to one Yb2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Mg2ZnN2 by Materials Project

Mg4ZnN4Zn is Tetraauricupride structured and crystallizes in the cubic P-43m space group. The structure is zero-dimensional and consists of one Mg4ZnN4 cluster and one zinc molecule. In the Mg4ZnN4 cluster, Mg2+ is bonded in a single-bond geometry to one N3- atom. The Mg–N bond length is 1.98 Å. Zn2+ is bonded in a tetrahedral geometry to four equivalent N3- atoms. All Zn–N bond lengths are 1.92 Å. N3- is bonded in a linear geometry to one Mg2+ and one Zn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2ZnSb2 by Materials Project

Na2ZnSb2 is alpha Niobium phosphide-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one Na2ZnSb2 cluster. Na1+ is bonded in a single-bond geometry to one Sb2- atom. The Na–Sb bond length is 2.99 Å. Zn2+ is bonded in a linear geometry to two equivalent Sb2- atoms. Both Zn–Sb bond lengths are 2.51 Å. Sb2- is bonded in a linear geometry to one Na1+ and one Zn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pr2S2F by Materials Project

Pr2S2F is alpha Niobium phosphide-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one Pr2S2F cluster. Pr is bonded in a linear geometry to one S and one F atom. The Pr–S bond length is 2.39 Å. The Pr–F bond length is 2.48 Å. S is bonded in a single-bond geometry to one Pr atom. F is bonded in a linear geometry to two equivalent Pr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on La2I2O by Materials Project

La2OI2 crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one La2OI2 cluster. La2+ is bonded in a linear geometry to one O2- and one I1- atom. The La–O bond length is 2.11 Å. The La–I bond length is 2.98 Å. O2- is bonded in a linear geometry to two equivalent La2+ atoms. I1- is bonded in a single-bond geometry to one La2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Tl2CuSe2 by Materials Project

CuTl2Se2 crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one CuTl2Se2 cluster. Cu2+ is bonded in a linear geometry to two equivalent Se2- atoms. Both Cu–Se bond lengths are 2.22 Å. Tl1+ is bonded in a single-bond geometry to one Se2- atom. The Tl–Se bond length is 2.64 Å. Se2- is bonded in a linear geometry to one Cu2+ and one Tl1+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb2NaO2 by Materials Project

Rb2NaO2 is alpha Niobium phosphide-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one Rb2NaO2 cluster. Rb is bonded in a single-bond geometry to one O atom. The Rb–O bond length is 2.35 Å. Na is bonded in a linear geometry to two equivalent O atoms. Both Na–O bond lengths are 2.18 Å. O is bonded in a linear geometry to one Rb and one Na atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr2I2F by Materials Project

Sr2I2F is Cyanogen Chloride-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one Sr2I2F cluster. Sr is bonded in a linear geometry to one I and one F atom. The Sr–I bond length is 2.94 Å. The Sr–F bond length is 2.30 Å. I is bonded in a single-bond geometry to one Sr atom. F is bonded in a linear geometry to two equivalent Sr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on C7I3N4 by Materials Project

C14N8I3(I)3 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of two C14N8I3 clusters and two I clusters. In each C14N8I3 cluster, there are seven inequivalent C+2.14+ sites. In the first C+2.14+ site, C+2.14+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.59 Å. In the second C+2.14+ site, C+2.14+ is bonded in a distorted bent 150 degrees geometry to two N3- atoms. There is one shorter (1.34 Å) and one longer (1.39 Å) C–N bond length. In the third C+2.14+ site, C+2.14+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.47 Å. In the fourth C+2.14+ site, C+2.14+ is bonded in a distorted bent 120 degrees geometry to two N3- atoms. There is one shorter (1.32 Å) and one longer (1.39 Å) C–N bond length. In the fifth C+2.14+ site, C+2.14+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.20 Å. In the sixth C+2.14+ site, C+2.14+ is bonded in a distorted trigonal planar geometry to two N3- and one I1- atom. There is one shorter (1.29 Å) and one longer (1.36 Å) C–N bond length. The C–I bond length is 2.11 Å. In the seventh C+2.14+ site, C+2.14+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.19 Å. There are four inequivalent N3- sites. In the first N3- site, N3- is bonded in a linear geometry to two C+2.14+ atoms. In the second N3- site, N3- is bonded in a 3-coordinate geometry to three C+2.14+ atoms. In the third N3- site, N3- is bonded in a 2-coordinate geometry to three C+2.14+ atoms. In the fourth N3- site, N3- is bonded in a linear geometry to two C+2.14+ atoms. There are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a linear geometry to two equivalent I1- atoms. Both I–I bond lengths are 3.55 Å. In the second I1- site, I1- is bonded in a single-bond geometry to one C+2.14+ and one I1- atom. In each I cluster, there are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a linear geometry to two equivalent I1- atoms. Both I–I bond lengths are 2.88 Å. In the second I1- site, I1- is bonded in a distorted single-bond geometry to one I1- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Yb2I2F by Materials Project

Yb2I2F is Cyanogen Chloride-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one Yb2I2F cluster. Yb is bonded in a linear geometry to one I and one F atom. The Yb–I bond length is 2.82 Å. The Yb–F bond length is 2.12 Å. I is bonded in a single-bond geometry to one Yb atom. F is bonded in a linear geometry to two equivalent Yb atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Na2MnSb2 by Materials Project

Na2MnSb2 crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one Na2MnSb2 cluster. Na1+ is bonded in a single-bond geometry to one Sb2- atom. The Na–Sb bond length is 2.97 Å. Mn2+ is bonded in a linear geometry to two equivalent Sb2- atoms. Both Mn–Sb bond lengths are 2.51 Å. Sb2- is bonded in a linear geometry to one Na1+ and one Mn2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

White Paper On Nuclear Structure Reactions and Astrophysics

In preparation for the 2023 NSAC Long Range Plan (LRP), the DNP Town Meeting on Nuclear Structure, Reactions, and Astrophysics was held at Argonne National Laboratory (ANL) on Nov 14-16, 2022. The town meeting brought together 578 members of the low-energy nuclear science community, including 216 in-person attendees and 362 remote participants coming from US national laboratories, a wide range of US universities and other research institutions and universities abroad. Participants met in five topic-oriented and seven cross-cutting and intersecting working groups to discuss progress since the 2015 LRP and identify compelling science opportunities and the resources needed to realize them. These considerations were used during the Town Meeting to determine a set of resolutions outlining the highest priorities for our subfield. The full text of the resolutions endorsed by unanimous consent by the low-energy nuclear science community at the Town Meeting is presented at the end of this executive summary. The reports from all working groups that met during the Town Meeting are included as Secs. 1 to 11 of this Whitepaper. The intellectual challenges for nuclear structure, reactions and astrophysics can be captured in the following questions: What is the nature of the nuclear force that binds protons and neutrons into stable nuclei and rare isotopes, and how do the rich phenomena of nuclear structure and reactions emerge? How do single-nucleon, cluster, and collective degrees of freedom coexist and evolve with increasing proton-neutron imbalance and excitation energies? What are the limits of nuclear existence, and what features arise near and beyond these limits? What are the astrophysical origins of the elements and how did the associated chemical evolution proceed? How do stars evolve, and what nuclear signatures do they leave behind? What is the nature of neutron stars and dense matter? How can the knowledge and technological progress provided by nuclear science best be used to benefit society?

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1973

High voltage electron microscopy of lunar samples

Lunar pyroxenes from Apollo 11, 12, 14, and 15 were investigated. The iron-rich and magnesium-rich pyroxene specimens were crushed to a grain size of ca. 50 microns and studied by a combination of X-ray and electron diffraction, electron microscopy, 57 Fe Mossbauer spectroscopy and X-ray crystallography techniques. Highly ordered, uniform electron-dense bands, corresponding to exsolution lamellae, with average widths of ca. 230A to 1000A dependent on the source specimen were observed. These were?qr separated by wider, less-dense interband spacings with average widths of ca. 330A to 3100A. In heating experiments, splitting of the dense bands into finer structures, leading finally to obliteration of the exsolution lamellae was recorded. The extensive exsolution is evidence for significantly slower cooling rates, or possibly annealing, at temperatures in the subsolidus range, adding evidence that annealing of rock from the surface of the moon took place at ca. 600 C. Correlation of the band structure with magnetic ordering at low temperatures and iron clustering within the bands was studied.

Fernandez-Moran, H.↗