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All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Charging and hybridization in the finite cluster model

Cluster wavefunctions which have appropriate hybridization and polarization lead to reasonable properties for the interaction of an adsorbate with a solid surface. However, for Al clusters, it was found that the atomic change distribution is not uniform. The finite cluster size leads to changes not representative for an extended system. This effect appears to be dependent on the particular materials being studied; it does not occur in all cases.

Bauschlicher, C. W., Jr.↗
DOE OSTI2020

Materials Data on B24N4O by Materials Project

(B)10NB3B7N2B4NO crystallizes in the orthorhombic Pna2_1 space group. The structure is zero-dimensional and consists of forty boron molecules, four triborylamine molecules, four B4NO clusters, and four B7N2 clusters. In each B4NO cluster, there are four inequivalent B+0.50+ sites. In the first B+0.50+ site, B+0.50+ is bonded in a bent 120 degrees geometry to one N+2.50- and one O2- atom. The B–N bond length is 1.48 Å. The B–O bond length is 1.41 Å. In the second B+0.50+ site, B+0.50+ is bonded in a single-bond geometry to one N+2.50- atom. The B–N bond length is 1.50 Å. In the third B+0.50+ site, B+0.50+ is bonded in a single-bond geometry to one O2- atom. The B–O bond length is 1.48 Å. In the fourth B+0.50+ site, B+0.50+ is bonded in a single-bond geometry to one N+2.50- atom. The B–N bond length is 1.49 Å. N+2.50- is bonded in a trigonal planar geometry to three B+0.50+ atoms. O2- is bonded in a distorted bent 120 degrees geometry to two B+0.50+ atoms. In each B7N2 cluster, there are seven inequivalent B+0.50+ sites. In the first B+0.50+ site, B+0.50+ is bonded in a single-bond geometry to one N+2.50- atom. The B–N bond length is 1.55 Å. In the second B+0.50+ site, B+0.50+ is bonded in a single-bond geometry to one N+2.50- atom. The B–N bond length is 1.59 Å. In the third B+0.50+ site, B+0.50+ is bonded in a single-bond geometry to one N+2.50- atom. The B–N bond length is 1.59 Å. In the fourth B+0.50+ site, B+0.50+ is bonded in a water-like geometry to two N+2.50- atoms. There is one shorter (1.54 Å) and one longer (1.57 Å) B–N bond length. In the fifth B+0.50+ site, B+0.50+ is bonded in a single-bond geometry to one N+2.50- atom. The B–N bond length is 1.53 Å. In the sixth B+0.50+ site, B+0.50+ is bonded in a single-bond geometry to one N+2.50- atom. The B–N bond length is 1.63 Å. In the seventh B+0.50+ site, B+0.50+ is bonded in a single-bond geometry to one N+2.50- atom. The B–N bond length is 1.65 Å. There are two inequivalent N+2.50- sites. In the first N+2.50- site, N+2.50- is bonded to four B+0.50+ atoms to form corner-sharing NB4 tetrahedra. In the second N+2.50- site, N+2.50- is bonded to four B+0.50+ atoms to form distorted corner-sharing NB4 tetrahedra.

36 MATERIALS SCIENCE↗
NASA NTRS1993

Nucleation of the diamond phase in aluminium-solid solutions

Precipitation was studied from fcc solid solutions with silicon, germanium, copper and magnesium. Of all these elements only silicon and germanium form diamond cubic (DC) precipitates in fcc Al. Nucleation of the DC structure is enhanced if both types of atom are dissolved in the fcc lattice. This is interpreted as due to atomic size effects in the prenucleation stage. There are two modes of interference of fourth elements with nucleation of the DC phase in Al + Si, Ge. The formation of the DC phase is hardly affected if the atoms (for example, copper) are rejected from the (Si, Ge)-rich clusters. If additional types of atom are attracted by silicon and/or germanium, DC nuclei are replaced by intermetallic compounds (for example Mg2Si).

Hornbogen, E.↗
DOE OSTI2020

Materials Data on Mo2P4C14SNCl4 by Materials Project

Mo2C5PNSCl4(PC3)3 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of four allylphosphine molecules, one Mo2C5PNSCl4 cluster, and one PC3 cluster. In the Mo2C5PNSCl4 cluster, there are two inequivalent Mo6+ sites. In the first Mo6+ site, Mo6+ is bonded in a distorted rectangular see-saw-like geometry to one N3-, one S2-, and two Cl1- atoms. The Mo–N bond length is 1.81 Å. The Mo–S bond length is 2.35 Å. There are one shorter (2.41 Å) and one longer (2.44 Å) Mo–Cl bond lengths. In the second Mo6+ site, Mo6+ is bonded in a rectangular see-saw-like geometry to one S2- and three Cl1- atoms. The Mo–S bond length is 2.30 Å. There are a spread of Mo–Cl bond distances ranging from 2.35–2.45 Å. There are five inequivalent C+1.64- sites. In the first C+1.64- site, C+1.64- is bonded in a distorted linear geometry to one C+1.64- and one N3- atom. The C–C bond length is 1.29 Å. The C–N bond length is 1.26 Å. In the second C+1.64- site, C+1.64- is bonded in a single-bond geometry to one C+1.64- atom. In the third C+1.64- site, C+1.64- is bonded in a 3-coordinate geometry to two C+1.64- and one P5+ atom. There is one shorter (1.38 Å) and one longer (1.54 Å) C–C bond length. The C–P bond length is 1.83 Å. In the fourth C+1.64- site, C+1.64- is bonded in a 3-coordinate geometry to three C+1.64- atoms. Both C–C bond lengths are 1.39 Å. In the fifth C+1.64- site, C+1.64- is bonded in a 3-coordinate geometry to two C+1.64- and one P5+ atom. The C–P bond length is 1.77 Å. P5+ is bonded in a 3-coordinate geometry to two C+1.64- and one Cl1- atom. The P–Cl bond length is 2.75 Å. N3- is bonded in a linear geometry to one Mo6+ and one C+1.64- atom. S2- is bonded in a 2-coordinate geometry to two Mo6+ atoms. There are four inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 2-coordinate geometry to two Mo6+ atoms. In the second Cl1- site, Cl1- is bonded in a 1-coordinate geometry to one Mo6+ and one P5+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Mo6+ atom. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Mo6+ atom. In the PC3 cluster, there are three inequivalent C+1.64- sites. In the first C+1.64- site, C+1.64- is bonded in a 3-coordinate geometry to three C+1.64- atoms. There is one shorter (1.38 Å) and two longer (1.39 Å) C–C bond length. In the second C+1.64- site, C+1.64- is bonded in a 1-coordinate geometry to two C+1.64- and one P5+ atom. The C–C bond length is 1.51 Å. The C–P bond length is 1.76 Å. In the third C+1.64- site, C+1.64- is bonded in a 3-coordinate geometry to two C+1.64- and one P5+ atom. The C–P bond length is 1.79 Å. P5+ is bonded in a 1-coordinate geometry to two C+1.64- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H12Pd(I2N)4 by Materials Project

PdN4H12(I)8 crystallizes in the monoclinic P2_1/m space group. The structure is zero-dimensional and consists of two hydriodic acid molecules, four I clusters, and two PdN4H12 clusters. In two of the I clusters, there are three inequivalent I1- sites. In the first I1- site, I1- is bonded in a 3-coordinate geometry to one I1- atom. The I–I bond length is 3.18 Å. In the second I1- site, I1- is bonded in a linear geometry to two I1- atoms. The I–I bond length is 2.84 Å. In the third I1- site, I1- is bonded in a distorted single-bond geometry to one I1- atom. In two of the I clusters, there are four inequivalent I1- sites. In the first I1- site, I1- is bonded in a 1-coordinate geometry to one I1- atom. The I–I bond length is 2.96 Å. In the second I1- site, I1- is bonded in a distorted linear geometry to two I1- atoms. The I–I bond length is 2.96 Å. In the third I1- site, I1- is bonded in a distorted L-shaped geometry to two I1- atoms. The I–I bond length is 3.26 Å. In the fourth I1- site, I1- is bonded in a 2-coordinate geometry to one I1- atom. In each PdN4H12 cluster, Pd2+ is bonded in a rectangular see-saw-like geometry to four N+1.50- atoms. There are two shorter (2.06 Å) and two longer (2.09 Å) Pd–N bond lengths. There are two inequivalent N+1.50- sites. In the first N+1.50- site, N+1.50- is bonded in a distorted trigonal non-coplanar geometry to one Pd2+ and three H1+ atoms. There is one shorter (1.02 Å) and two longer (1.03 Å) N–H bond length. In the second N+1.50- site, N+1.50- is bonded in a distorted trigonal non-coplanar geometry to one Pd2+ and three H1+ atoms. All N–H bond lengths are 1.03 Å. There are six inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N+1.50- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N+1.50- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N+1.50- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N+1.50- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N+1.50- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one N+1.50- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Explosive nucleation and growth of Pb islands on Ge(111) below room temperature via collective diffusion

Nucleation is a fundamental process in nature controlling phase transitions and pattern formation. Classical nucleation is based on the gradual aggregation of diffusing atoms after a critical cluster size is reached. Contrary to these expectations, we have observed in real time the formation of perfect Pb(111) islands with more than 10 5 atoms emerging out of the compressed wetting layer within a few seconds during growth of Pb on Ge(111) below room temperature. Pb deposited on Ge(111) in a temperature range between −30 °C and 10 °C exhibited explosive nucleation of height-selected islands upon reaching a critical coverage of 1.33 ± 0.07 ML with respect to Ge(111). Island nucleation was fueled by the 2% compression of the Pb wetting layer at the critical coverage. The island areas grew linearly with time, exhibiting collective diffusion, where thousands of atoms follow correlated, non-random walk diffusion. The total growth rate was higher with increasing temperature. Density functional theory simulations of the chemical potential and binding sites of the Pb/Ge(111) system give insight into the role of the compression of the wetting layer and the strain within the growing Pb layers, which explain this nonclassical behavior of the system.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
NASA NTRS1983

A potential energy scaling Monte Carlo simulation of thin film nucleation and growth

The initial growth of thin Ge fims on the (100) surface of an Fe substrate is investigated theoretically by means of Monte Carlo simulations based on a potential-energy-scaling technique. The substrate is modeled as a 20 x 20-square array with periodic boundary conditions, as described by Heinbockel et al. (1983), and the movement of surface atoms under the influence of the substrate interaction potential and the lateral interaction of neighboring atoms is explored via continuous updating (on the time scale of single events) of the potential energy at each site in the array. Results for the clustering of nine dispersed atoms over 1.0 s at 600 K and for deposition at 5 x 10 to the -14th/sq cm s over 2.0 s at 500 K are presented graphically.

Outlaw, R. A.↗
DOE OSTI2022

A computational study of Al n - and Al n -1 1Pt - clusters: the effects of doping and a uniform tuning gauge for single-atom nanocatalysts

Results of density functional theory calculations on Al n - and Al n -1 1Pt - , n = 2-8, clusters are presented and analyzed. The analysis includes different structural forms of the clusters characterized in terms of binding energy, spin and symmetry, and a comparative evaluation of various properties of the two systems viewed as connected through a single-Pt substitutional doping and examined in terms of their respective most stable structures. Furthermore, the Al n -1 1Pt - clusters are then used as a paradigmatic (model) case of single-atom nanocatalysts, with Pt as the catalytic center and Al n-1 as its support, to implement a uniform descriptor for gauging the tuning effects of all the parameters ( "knobs ") of a nanocatalyst that include the identity of the active center and the material and size of its support.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2020

Materials Data on Fe6Sn2(CO)23 by Materials Project

(Fe(CO)4)4(Fe(CO)3)2(Sn)2CO crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of four 7440-31-5 molecules, two formaldehyde molecules, four Fe(CO)3 clusters, and eight Fe(CO)4 clusters. In two of the Fe(CO)3 clusters, Fe3+ is bonded in a 3-coordinate geometry to three C+0.87+ atoms. There is one shorter (1.78 Å) and two longer (1.79 Å) Fe–C bond length. There are three inequivalent C+0.87+ sites. In the first C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the second C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.17 Å. In the third C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In two of the Fe(CO)3 clusters, Fe3+ is bonded in a 3-coordinate geometry to three C+0.87+ atoms. There is two shorter (1.79 Å) and one longer (1.80 Å) Fe–C bond length. There are three inequivalent C+0.87+ sites. In the first C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the second C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the third C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In two of the Fe(CO)4 clusters, Fe3+ is bonded in a distorted see-saw-like geometry to four C+0.87+ atoms. There are a spread of Fe–C bond distances ranging from 1.77–1.81 Å. There are four inequivalent C+0.87+ sites. In the first C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the second C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the third C+0.87+ site, C+0.87+ is bonded in a distorted single-bond geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the fourth C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In two of the Fe(CO)4 clusters, Fe3+ is bonded in a see-saw-like geometry to four C+0.87+ atoms. There are a spread of Fe–C bond distances ranging from 1.77–1.81 Å. There are four inequivalent C+0.87+ sites. In the first C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the second C+0.87+ site, C+0.87+ is bonded in a linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the third C+0.87+ site, C+0.87+ is bonded in a distorted single-bond geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the fourth C+0.87+ site, C+0.87+ is bonded in a distorted single-bond geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In four of the Fe(CO)4 clusters, Fe3+ is bonded in a see-saw-like geometry to four C+0.87+ atoms. There are a spread of Fe–C bond distances ranging from 1.77–1.81 Å. There are four inequivalent C+0.87+ sites. In the first C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the second C+0.87+ site, C+0.87+ is bonded in a distorted single-bond geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the third C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. In the fourth C+0.87+ site, C+0.87+ is bonded in a distorted linear geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one C+0.87+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

How the Arrangement of Platinum Atoms on Ruthenium Nanoparticles Improves Hydrogen Evolution Activity

The platinum‐ruthenium (PtRu) system is highly active for hydrogen evolution reaction (HER) in alkaline media with both Pt and Ru playing active roles in the water dissociation step that generates adsorbed hydrogen atoms. Precise control of the arrangement of Pt atoms on Ru nanoparticles can maximize the Pt‐Ru sites for water dissociation and Pt‐Pt sites for hydrogen production and can considerably improve HER catalytic performance. By directing the growth and distribution of Pt on Ru hourglass nanoparticles, the arrangement of Pt on Ru is controlled into forming Pt islands, small Pt clusters, and strings of a few Pt atoms. Calculations show that the unique atomic string arrangements of Pt on Ru is the thermodynamically favorable configuration. Additionally, these strings have a favorable combination of Pt‐Ru and Pt‐Pt sites, making the Pt‐string on Ru the most active catalyst with a more than fivefold increase in turnover frequency for alkaline HER compared to the Pt‐island on Ru catalyst. The results show how controlling the Pt atomic arrangement on Ru nanoparticle surfaces for the tuning of Pt‐Pt and Pt‐Ru neighboring sites can direct toward a more efficient HER mechanism and thereby significantly enhancing HER performance.

36 MATERIALS SCIENCE↗
DOE OSTI2023

The MeerKAT Fornax Survey: II. The rapid removal of H I from dwarf galaxies in the Fornax cluster

We present MeerKAT Fornax Survey atomic hydrogen (H I) observations of the dwarf galaxies located in the central ~2.5 × 4 deg 2 of the Fornax galaxy cluster (R vir ~2°). The H I images presented in this work have a 3σ column density sensitivity between 2.7 and 50 × 10 18 cm –2 over 25 km s –1 for spatial resolution between 4 and 1 kpc. We are able to detect an impressive M HI = 5 × 10 5 M ⊙ 3σ point source with a line width of 50 km s –1 at a distance of 20 Mpc. We detected H I in 17 out of the 304 dwarfs in our field, with 14 out of the 36 late-type dwarfs (LTDs) and three out of the 268 early-type dwarfs (ETDs). The H I-detected LTDs have likely just joined the cluster and are on their first infall as they are located at large clustocentric radii, with comparable MHI and mean stellar surface brightness at fixed luminosity as blue, star-forming LTDs in the field. By contrast, the H I-detected ETDs have likely been in the cluster longer than the LTDs and acquired their H I through a recent merger or accretion from nearby H I. Eight of the H I-detected LTDs host irregular or asymmetric H I emission and disturbed or lopsided stellar emission. There are two clear cases of ram pressure shaping the H I, with the LTDs displaying compressed H I on the side closest to the cluster centre and a one-sided, starless tail pointing away from the cluster centre. The H I-detected dwarfs avoid the most massive potentials (i.e. cluster centre and massive galaxies), consistent with massive galaxies playing an active role in the removal of H I. We created a simple toy model to quantify the timescale of H I stripping in the cluster by reproducing the observed M r' –M HI relation. We find that a M HI = 10 8 M ⊙ dwarf is stripped in ~240 Myr. The model is consistent with our observations, where low-mass LTDs are directly stripped of their H I from a single encounter and more massive LTDs can harbour a disturbed H I morphology due to longer times or multiple encounters being required to fully strip their H I. This is the first time dwarf galaxies with M HI ≲ 1 × 10 6 M ⊙ have been detected and resolved beyond the local group and in a galaxy cluster.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Materials Data on AgSbTe6S16(OF5)6 by Materials Project

AgS16SbTe6(OF5)6 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of one AgS16 cluster and one SbTe6(OF5)6 cluster. In the AgS16 cluster, Ag1+ is bonded in a distorted linear geometry to four S atoms. There are two shorter (2.66 Å) and two longer (3.04 Å) Ag–S bond lengths. There are eight inequivalent S sites. In the first S site, S is bonded in a water-like geometry to two S atoms. There are one shorter (2.05 Å) and one longer (2.07 Å) S–S bond lengths. In the second S site, S is bonded in a water-like geometry to two S atoms. The S–S bond length is 2.06 Å. In the third S site, S is bonded in a water-like geometry to two S atoms. There are one shorter (2.05 Å) and one longer (2.08 Å) S–S bond lengths. In the fourth S site, S is bonded in a distorted trigonal non-coplanar geometry to one Ag1+ and two S atoms. In the fifth S site, S is bonded in a water-like geometry to two S atoms. There are one shorter (2.05 Å) and one longer (2.06 Å) S–S bond lengths. In the sixth S site, S is bonded in a water-like geometry to two S atoms. The S–S bond length is 2.08 Å. In the seventh S site, S is bonded in a water-like geometry to two S atoms. In the eighth S site, S is bonded in a trigonal non-coplanar geometry to one Ag1+ and two S atoms. In the SbTe6(OF5)6 cluster, Sb5+ is bonded to six O2- atoms to form SbO6 octahedra that share corners with six TeOF5 octahedra. The corner-sharing octahedra tilt angles range from 41–42°. All Sb–O bond lengths are 2.00 Å. There are three inequivalent Te6+ sites. In the first Te6+ site, Te6+ is bonded to one O2- and five F1- atoms to form TeOF5 octahedra that share a cornercorner with one SbO6 octahedra. The corner-sharing octahedral tilt angles are 41°. The Te–O bond length is 1.89 Å. There is one shorter (1.87 Å) and four longer (1.88 Å) Te–F bond length. In the second Te6+ site, Te6+ is bonded to one O2- and five F1- atoms to form TeOF5 octahedra that share a cornercorner with one SbO6 octahedra. The corner-sharing octahedral tilt angles are 42°. The Te–O bond length is 1.89 Å. All Te–F bond lengths are 1.88 Å. In the third Te6+ site, Te6+ is bonded to one O2- and five F1- atoms to form TeOF5 octahedra that share a cornercorner with one SbO6 octahedra. The corner-sharing octahedral tilt angles are 41°. The Te–O bond length is 1.89 Å. There is one shorter (1.87 Å) and four longer (1.88 Å) Te–F bond length. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Sb5+ and one Te6+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Sb5+ and one Te6+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Sb5+ and one Te6+ atom. There are fifteen inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the third F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the fourth F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the fifth F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the sixth F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the seventh F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the eighth F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the ninth F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the tenth F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the eleventh F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the twelfth F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the thirteenth F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the fourteenth F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom. In the fifteenth F1- site, F1- is bonded in a single-bond geometry to one Te6+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS1973

The characteristics of a possible low altitude electron layer in the Martian atmosphere

The apparent diurnal Martian surface pressure variation, as deduced from radio occultation experiments, is discussed and explained as possibly arising from the effect of a low altitude electron layer. Possible source and loss mechanisms for the low altitude electron layer are presented and discussed. Time-dependent differential equations describing the electron layer are derived and then integrated to investigate the electron distribution resulting from the several processes that might occur in the atmosphere. It is concluded that the source mechanism is the sublimation of alkali atoms from a permanent dust layer (a dust layer of 0.2 micron particles of density 9/cu cm is sufficient), and that the dominant loss process must involve CO2 clustering to the alkali atoms. Using these processes, an electron layer is developed which would explain the apparent diurnal surface pressure.

Wallio, H. A.↗
NASA NTRS1996

The Structure and Stability of B(n)H(+) Clusters

The geometries of the B(n)H(+) clusters for n=1-13 have been optimized at the B3LYP level of theory. Excluding B2H(+) all clusters are low-spin coupled. The structures appear to be related to the bare B(+)(n) clusters in two ways: 1) an H atom is added to the B(+)(n) cluster or 2) a BH is added to the B(+)(n-1) cluster. The B(+)(n)-H binding energies are computed at the B3LYP level of theory, and calibrated n using the CCSD(T) level of theory. The computed results tend to fall between the experimental best estimates and the experimental lower bounds. The B(+)(n)-H binding energies show an inverse correspondence with the B+(n-1)-B values) while the B(+)(n-1)-B and B(+)(n-1)-BH results tend to parallel each other.

Ricca, Alessandra↗
DOE OSTI2020

Materials Data on Os5(CO)16 by Materials Project

(Os(CO)3)4Os(CO)4 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of eight Os(CO)3 clusters and two Os(CO)4 clusters. In two of the Os(CO)3 clusters, Os+1.60- is bonded in a 3-coordinate geometry to three C+2.50+ atoms. There are a spread of Os–C bond distances ranging from 1.87–1.93 Å. There are three inequivalent C+2.50+ sites. In the first C+2.50+ site, C+2.50+ is bonded in a linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.17 Å. In the second C+2.50+ site, C+2.50+ is bonded in a 1-coordinate geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.17 Å. In the third C+2.50+ site, C+2.50+ is bonded in a distorted linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.16 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In two of the Os(CO)3 clusters, Os+1.60- is bonded in a 3-coordinate geometry to three C+2.50+ atoms. There is one shorter (1.90 Å) and two longer (1.92 Å) Os–C bond length. There are three inequivalent C+2.50+ sites. In the first C+2.50+ site, C+2.50+ is bonded in a distorted linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.17 Å. In the second C+2.50+ site, C+2.50+ is bonded in a distorted linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.16 Å. In the third C+2.50+ site, C+2.50+ is bonded in a distorted linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.17 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In two of the Os(CO)3 clusters, Os+1.60- is bonded in a 3-coordinate geometry to three C+2.50+ atoms. There is two shorter (1.89 Å) and one longer (1.92 Å) Os–C bond length. There are three inequivalent C+2.50+ sites. In the first C+2.50+ site, C+2.50+ is bonded in a linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.16 Å. In the second C+2.50+ site, C+2.50+ is bonded in a linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.16 Å. In the third C+2.50+ site, C+2.50+ is bonded in a linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.16 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In two of the Os(CO)3 clusters, Os+1.60- is bonded in a 3-coordinate geometry to three C+2.50+ atoms. There are a spread of Os–C bond distances ranging from 1.87–1.91 Å. There are three inequivalent C+2.50+ sites. In the first C+2.50+ site, C+2.50+ is bonded in a linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.16 Å. In the second C+2.50+ site, C+2.50+ is bonded in a distorted linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.17 Å. In the third C+2.50+ site, C+2.50+ is bonded in a linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.17 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In each Os(CO)4 cluster, Os+1.60- is bonded in a rectangular see-saw-like geometry to four C+2.50+ atoms. There are a spread of Os–C bond distances ranging from 1.91–1.97 Å. There are four inequivalent C+2.50+ sites. In the first C+2.50+ site, C+2.50+ is bonded in a distorted linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.16 Å. In the second C+2.50+ site, C+2.50+ is bonded in a linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.15 Å. In the third C+2.50+ site, C+2.50+ is bonded in a distorted linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.16 Å. In the fourth C+2.50+ site, C+2.50+ is bonded in a linear geometry to one Os+1.60- and one O2- atom. The C–O bond length is 1.16 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one C+2.50+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CrH18I7N6 by Materials Project

Cr(NH3)6(I)7 crystallizes in the monoclinic C2/m space group. The structure is zero-dimensional and consists of two Cr(NH3)6 clusters and four I clusters. In each Cr(NH3)6 cluster, Cr3+ is bonded in an octahedral geometry to six N+2.33- atoms. All Cr–N bond lengths are 2.10 Å. There are two inequivalent N+2.33- sites. In the first N+2.33- site, N+2.33- is bonded in a distorted trigonal non-coplanar geometry to one Cr3+ and three H1+ atoms. All N–H bond lengths are 1.03 Å. In the second N+2.33- site, N+2.33- is bonded in a distorted trigonal non-coplanar geometry to one Cr3+ and three H1+ atoms. All N–H bond lengths are 1.03 Å. There are five inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one N+2.33- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one N+2.33- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one N+2.33- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one N+2.33- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one N+2.33- atom. In two of the I clusters, there are two inequivalent I1- sites. In the first I1- site, I1- is bonded in a 1-coordinate geometry to one I1- atom. The I–I bond length is 3.37 Å. In the second I1- site, I1- is bonded in a distorted linear geometry to two I1- atoms. The I–I bond length is 2.87 Å. In two of the I clusters, 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 2.94 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 SbSe3N2Cl7 by Materials Project

SbCl6N2Se3Cl is Modderite-like structured and crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of two N2Se3Cl clusters and two SbCl6 clusters. In each N2Se3Cl cluster, there are two inequivalent N5+ sites. In the first N5+ site, N5+ is bonded in a bent 120 degrees geometry to two Se2- atoms. There is one shorter (1.74 Å) and one longer (1.79 Å) N–Se bond length. In the second N5+ site, N5+ is bonded in a bent 120 degrees geometry to two Se2- atoms. Both N–Se bond lengths are 1.74 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a water-like geometry to two N5+ atoms. In the second Se2- site, Se2- is bonded in a single-bond geometry to one N5+ atom. In the third Se2- site, Se2- is bonded in a distorted water-like geometry to one N5+ and one Cl1- atom. The Se–Cl bond length is 2.29 Å. Cl1- is bonded in a single-bond geometry to one Se2- atom. In one of the SbCl6 clusters, Sb3+ is bonded in an octahedral geometry to six Cl1- atoms. There are a spread of Sb–Cl bond distances ranging from 2.40–2.45 Å. There are six inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Sb3+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the fifth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Sb3+ atom. In the sixth Cl1- site, Cl1- is bonded in a distorted single-bond geometry to one Sb3+ atom. In one of the SbCl6 clusters, Sb3+ is bonded in an octahedral geometry to six Cl1- atoms. There are a spread of Sb–Cl bond distances ranging from 2.40–2.43 Å. There are six inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the fifth Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom. In the sixth Cl1- site, Cl1- is bonded in a single-bond geometry to one Sb3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Understanding Superatomic Ag Nanohydrides

Abstract Bulk Ag hydrides are extremely challenging to make even at very high pressures, but they may become stable as the particle size shrinks to the nanometer regime. Here, the formation and electronic structure of Ag nanohydrides are investigated from a superatomic perspective by density functional theory. It is found that as the coverage increases, adsorption energy of hydrogen atoms on Ag 38 cluster to form Ag 38 H 2 n nanohydride ( n is from 1 to 15) can be energetically favorable with respect to bare Ag 38 and H 2 . Furthermore, the adsorbed hydrogen atoms contribute their 1s electrons to the superatom electron count and behave as a metal instead of a ligand. The electronic structure of the silver nanohydrides follows the superatomic complex model, leading to magic or relatively more stable compositions such as Ag 38 H 2 , Ag 38 H 20 , and Ag 38 H 30 , which correspond to 40‐electron, 58‐electron, and 68‐electron shell closings, respectively. Angular momentum analyses of the superatomic orbitals suggest a convoluted interaction of geometry, symmetry, and orbital splitting.

He, Xiang↗