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DOE OSTI2020

Materials Data on Ho4CdPd by Materials Project

Ho4PdCd crystallizes in the cubic F-43m space group. The structure is three-dimensional. there are three inequivalent Ho sites. In the first Ho site, Ho is bonded in a 3-coordinate geometry to three equivalent Pd and three equivalent Cd atoms. All Ho–Pd bond lengths are 2.86 Å. All Ho–Cd bond lengths are 3.38 Å. In the second Ho site, Ho is bonded in a distorted bent 150 degrees geometry to two equivalent Pd and two equivalent Cd atoms. Both Ho–Pd bond lengths are 2.85 Å. Both Ho–Cd bond lengths are 3.51 Å. In the third Ho site, Ho is bonded in a 4-coordinate geometry to two equivalent Pd and two equivalent Cd atoms. Both Ho–Pd bond lengths are 3.53 Å. Both Ho–Cd bond lengths are 3.25 Å. Pd is bonded in a 6-coordinate geometry to nine Ho atoms. Cd is bonded to nine Ho and three equivalent Cd atoms to form a mixture of distorted face and corner-sharing CdHo9Cd3 cuboctahedra. All Cd–Cd bond lengths are 3.17 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho5Tl3 by Materials Project

Ho5Tl3 crystallizes in the hexagonal P6_3/mcm space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 6-coordinate geometry to six equivalent Tl atoms. All Ho–Tl bond lengths are 3.21 Å. In the second Ho site, Ho is bonded in a 3-coordinate geometry to five equivalent Tl atoms. There are a spread of Ho–Tl bond distances ranging from 3.14–3.68 Å. Tl is bonded in a 9-coordinate geometry to nine Ho atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho3Os by Materials Project

Ho3Os is Cementite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 3-coordinate geometry to three equivalent Os atoms. There are a spread of Ho–Os bond distances ranging from 2.85–3.16 Å. In the second Ho site, Ho is bonded in a distorted bent 150 degrees geometry to two equivalent Os atoms. There are one shorter (2.77 Å) and one longer (2.82 Å) Ho–Os bond lengths. Os is bonded in a 8-coordinate geometry to eight Ho atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho4CdNi by Materials Project

Ho4NiCd crystallizes in the cubic F-43m space group. The structure is three-dimensional. there are three inequivalent Ho sites. In the first Ho site, Ho is bonded in a 3-coordinate geometry to three equivalent Ni and three equivalent Cd atoms. All Ho–Ni bond lengths are 2.78 Å. All Ho–Cd bond lengths are 3.39 Å. In the second Ho site, Ho is bonded in a distorted bent 150 degrees geometry to two equivalent Ni and two equivalent Cd atoms. Both Ho–Ni bond lengths are 2.78 Å. Both Ho–Cd bond lengths are 3.45 Å. In the third Ho site, Ho is bonded in a 4-coordinate geometry to two equivalent Ni and two equivalent Cd atoms. Both Ho–Ni bond lengths are 3.44 Å. Both Ho–Cd bond lengths are 3.21 Å. Ni is bonded in a 6-coordinate geometry to nine Ho atoms. Cd is bonded to nine Ho and three equivalent Cd atoms to form a mixture of distorted face and corner-sharing CdHo9Cd3 cuboctahedra. All Cd–Cd bond lengths are 3.10 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho4CdIr by Materials Project

Ho4IrCd crystallizes in the cubic F-43m space group. The structure is three-dimensional. there are three inequivalent Ho sites. In the first Ho site, Ho is bonded in a 3-coordinate geometry to three equivalent Ir and three equivalent Cd atoms. All Ho–Ir bond lengths are 2.82 Å. All Ho–Cd bond lengths are 3.42 Å. In the second Ho site, Ho is bonded in a distorted bent 150 degrees geometry to two equivalent Ir and two equivalent Cd atoms. Both Ho–Ir bond lengths are 2.80 Å. Both Ho–Cd bond lengths are 3.48 Å. In the third Ho site, Ho is bonded in a 4-coordinate geometry to two equivalent Ir and two equivalent Cd atoms. Both Ho–Ir bond lengths are 3.47 Å. Both Ho–Cd bond lengths are 3.25 Å. Ir is bonded in a 6-coordinate geometry to nine Ho atoms. Cd is bonded to nine Ho and three equivalent Cd atoms to form a mixture of distorted face and corner-sharing CdHo9Cd3 cuboctahedra. All Cd–Cd bond lengths are 3.12 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho2(Ni2B)5 by Materials Project

Ho2(Ni2B)5 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 7-coordinate geometry to fifteen Ni and three B atoms. There are a spread of Ho–Ni bond distances ranging from 2.75–3.33 Å. There are a spread of Ho–B bond distances ranging from 2.72–2.85 Å. In the second Ho site, Ho is bonded in a 2-coordinate geometry to fourteen Ni and five B atoms. There are a spread of Ho–Ni bond distances ranging from 2.78–3.16 Å. There are a spread of Ho–B bond distances ranging from 2.71–3.05 Å. There are ten inequivalent Ni sites. In the first Ni site, Ni is bonded in a 4-coordinate geometry to three Ho and four B atoms. There are a spread of Ni–B bond distances ranging from 2.06–2.10 Å. In the second Ni site, Ni is bonded in a 4-coordinate geometry to two Ho and three B atoms. There are two shorter (2.06 Å) and one longer (2.10 Å) Ni–B bond lengths. In the third Ni site, Ni is bonded in a 3-coordinate geometry to three equivalent Ho and three B atoms. There are a spread of Ni–B bond distances ranging from 1.92–2.19 Å. In the fourth Ni site, Ni is bonded in a 12-coordinate geometry to three Ho and three B atoms. There are two shorter (2.03 Å) and one longer (2.06 Å) Ni–B bond lengths. In the fifth Ni site, Ni is bonded in a 2-coordinate geometry to three Ho and three B atoms. There are a spread of Ni–B bond distances ranging from 2.03–2.13 Å. In the sixth Ni site, Ni is bonded in a 1-coordinate geometry to three equivalent Ho and two B atoms. There are one shorter (2.02 Å) and one longer (2.22 Å) Ni–B bond lengths. In the seventh Ni site, Ni is bonded in a 2-coordinate geometry to four Ho and three B atoms. There are a spread of Ni–B bond distances ranging from 2.05–2.13 Å. In the eighth Ni site, Ni is bonded in a 3-coordinate geometry to three equivalent Ho and three B atoms. There are a spread of Ni–B bond distances ranging from 1.97–2.06 Å. In the ninth Ni site, Ni is bonded in a 3-coordinate geometry to three equivalent Ho and three B atoms. There are a spread of Ni–B bond distances ranging from 2.02–2.09 Å. In the tenth Ni site, Ni is bonded in a 4-coordinate geometry to two Ho and four B atoms. There are a spread of Ni–B bond distances ranging from 2.05–2.13 Å. There are five inequivalent B sites. In the first B site, B is bonded in a 9-coordinate geometry to two equivalent Ho, six Ni, and one B atom. The B–B bond length is 1.91 Å. In the second B site, B is bonded in a 7-coordinate geometry to two equivalent Ho, six Ni, and one B atom. The B–B bond length is 1.72 Å. In the third B site, B is bonded in a 7-coordinate geometry to one Ho and seven Ni atoms. In the fourth B site, B is bonded in a 9-coordinate geometry to two equivalent Ho, six Ni, and one B atom. In the fifth B site, B is bonded in a 8-coordinate geometry to one Ho, six Ni, and one B atom.

36 MATERIALS SCIENCE↗

DOE OSTI2021

DyFe 2 O 4 : A new trigonal rare-earth ferrite grown by molecular-beam epitaxy

Using epitaxial stabilization, we synthesized single-phase (001)-oriented thin films of DyFe 2 O 4+x on (111) MgAl 2 O 4 substrates by molecular-beam epitaxy. The metastable DyFe 2 O 4 polymorph formed is isostructural to known trigonal ferrimagnetic RFe 2 O 4 phases with space group $R\bar{3}m$, where R = Ho to Lu. The epitaxial DyFe 2 O 4 thin films have two in-plane orientation relationships: [100] DyFe 2 O 4 || [$2\bar{1}1$] MgAl 2 O 4 plus a twin variant related by a 60° in-plane rotation. DyFe 2 O 4 is not bulk stable and has never been synthesized before. Indeed, it has been predicted to be on the edge energetically of what may be possible to stabilize. The fact that the RFe 2 O 4 phase is stable for all elements leading up to dysprosium (Ho–Lu) leads us to believe that DyFe 2 O 4 could be a “remnant metastable phase,” one which, given the right thermodynamic conditions, could become the lowest free energy phase. We find that although we are able to get structurally very close to $R\bar{3}m$ DyFe 2 O 4 , the films are not stoichiometric as they have an increased c lattice parameter, indicative of extra oxygen as is sometimes seen in other RFe2O4 phases. The unintended surplus oxygen opens questions regarding what may be achievable using such tricks as epitaxial stabilization to access metastable phases and whether this indeed constitutes “remnant metastability.”

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho2Sn5Rh3 by Materials Project

Ho2Rh3Sn5 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 8-coordinate geometry to two equivalent Rh and six Sn atoms. Both Ho–Rh bond lengths are 3.27 Å. There are a spread of Ho–Sn bond distances ranging from 3.15–3.20 Å. In the second Ho site, Ho is bonded in a 1-coordinate geometry to five Rh and eight Sn atoms. There are a spread of Ho–Rh bond distances ranging from 2.87–3.35 Å. There are a spread of Ho–Sn bond distances ranging from 3.14–3.37 Å. There are three inequivalent Rh sites. In the first Rh site, Rh is bonded in a 9-coordinate geometry to three Ho and six Sn atoms. There are a spread of Rh–Sn bond distances ranging from 2.67–2.88 Å. In the second Rh site, Rh is bonded in a 9-coordinate geometry to four equivalent Ho and five Sn atoms. There are a spread of Rh–Sn bond distances ranging from 2.61–2.80 Å. In the third Rh site, Rh is bonded in a 7-coordinate geometry to seven Sn atoms. There are a spread of Rh–Sn bond distances ranging from 2.72–2.83 Å. There are five inequivalent Sn sites. In the first Sn site, Sn is bonded in a 4-coordinate geometry to two equivalent Ho and four Rh atoms. In the second Sn site, Sn is bonded in a 6-coordinate geometry to two equivalent Ho and four Rh atoms. In the third Sn site, Sn is bonded in a 3-coordinate geometry to four Ho and three Rh atoms. In the fourth Sn site, Sn is bonded in a 12-coordinate geometry to four equivalent Ho and four Rh atoms. In the fifth Sn site, Sn is bonded in a 5-coordinate geometry to two equivalent Ho and three equivalent Rh atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Shock‐tube spectroscopic water measurements and detailed kinetics modeling of 1‐pentene and 3‐methyl‐1‐butene

Abstract To understand the effects of the chemical structure of two C 5 alkene isomers on their combustion properties, and to highlight the major chemical reactions occurring during their high‐temperature oxidation, water time histories were measured behind reflected shock waves for the oxidation of 1‐pentene (C 5 H 10 ‐1) and 3‐methyl‐1‐butene (3M1B) in 99.5% Ar. The experiments were carried out at three different equivalence ratios ( φ = 0.5, 1.0, and 2.0) at pressures and temperatures ranging from 1.29 to 1.47 atm and 1 331 to 1 877 K, respectively. The H 2 O quantification extends the database for 1‐pentene and provides new insights for 3M1B. These unique results were used to validate and to develop a new detailed kinetics model. Numerical predictions are presented, and the new model was able to capture the results with suitable accuracy, with 3M1B being notably more reactive than C 5 H 10 ‐1. Sensitivity and rate‐of‐production analyses were performed to help explain the results. Under the present conditions, the reactivity is rapidly initiated by molecular dissociation of a fraction of the pentene isomers. The initiation phase then induces H‐atom abstraction by active radicals (H, OH, O, HO 2 , and CH 3 ) to first produce alkenyl C 5 H 9 radicals (or an alkyl radical and an alkenyl radical by breaking a C─C bond) and subsequent, smaller fragments. The difference in terms of reactivity between the isomers is essentially due to the fact that 3M1B has one particularly weak tertiary allylic C─H bond, which allows for fast H‐atom abstraction compared with 1‐pentene.

Grégoire, Claire M.↗

DOE OSTI2020

Materials Data on Ho2Pt by Materials Project

Ho2Pt is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded to four equivalent Pt atoms to form a mixture of edge and corner-sharing HoPt4 tetrahedra. There are a spread of Ho–Pt bond distances ranging from 2.88–2.95 Å. In the second Ho site, Ho is bonded in a 3-coordinate geometry to three equivalent Pt atoms. There are one shorter (2.82 Å) and two longer (3.06 Å) Ho–Pt bond lengths. Pt is bonded in a 7-coordinate geometry to seven Ho atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho3(Al3Ru)4 by Materials Project

Ho3(RuAl3)4 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ho is bonded in a 5-coordinate geometry to four equivalent Ru and eleven Al atoms. All Ho–Ru bond lengths are 3.37 Å. There are a spread of Ho–Al bond distances ranging from 2.96–3.21 Å. There are two inequivalent Ru sites. In the first Ru site, Ru is bonded in a body-centered cubic geometry to eight Al atoms. There are two shorter (2.40 Å) and six longer (2.58 Å) Ru–Al bond lengths. In the second Ru site, Ru is bonded in a 12-coordinate geometry to four equivalent Ho and eight Al atoms. There are a spread of Ru–Al bond distances ranging from 2.55–2.69 Å. There are four inequivalent Al sites. In the first Al site, Al is bonded in a 3-coordinate geometry to three equivalent Ho and three equivalent Ru atoms. In the second Al site, Al is bonded in a 3-coordinate geometry to three equivalent Ho and three Ru atoms. In the third Al site, Al is bonded in a 2-coordinate geometry to two equivalent Ho and two equivalent Ru atoms. In the fourth Al site, Al is bonded in a distorted linear geometry to three equivalent Ho and two equivalent Ru atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho3(Al3Os)4 by Materials Project

Ho3(OsAl3)4 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ho is bonded in a 5-coordinate geometry to four equivalent Os and eleven Al atoms. All Ho–Os bond lengths are 3.37 Å. There are a spread of Ho–Al bond distances ranging from 2.96–3.22 Å. There are two inequivalent Os sites. In the first Os site, Os is bonded in a body-centered cubic geometry to eight Al atoms. There are two shorter (2.39 Å) and six longer (2.59 Å) Os–Al bond lengths. In the second Os site, Os is bonded in a 12-coordinate geometry to four equivalent Ho and eight Al atoms. There are a spread of Os–Al bond distances ranging from 2.55–2.68 Å. There are four inequivalent Al sites. In the first Al site, Al is bonded in a 3-coordinate geometry to three equivalent Ho and three equivalent Os atoms. In the second Al site, Al is bonded in a 3-coordinate geometry to three equivalent Ho and three Os atoms. In the third Al site, Al is bonded in a 2-coordinate geometry to two equivalent Ho and two equivalent Os atoms. In the fourth Al site, Al is bonded in a distorted linear geometry to three equivalent Ho and two equivalent Os atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2024

Quasi-Classical Trajectory Calculation of Rate Constants Using an Ab Initio Trained Machine Learning Model (aML-MD) with Multifidelity Data

Machine learning (ML) provides a great opportunity for the construction of models with improved accuracy in classical molecular dynamics (MD). However, the accuracy of a ML trained model is limited by the quality and quantity of the training data. Generating large sets of accurate ab initio training data can require significant computational resources. Furthermore, inconsistent or incompatible data with different accuracies obtained using different methods may lead to biased or unreliable ML models that do not accurately represent the underlying physics. Recently, transfer learning showed its potential for avoiding these problems as well as for improving the accuracy, efficiency, and generalization of ML models using multifidelity data. In this work, ab initio trained ML-based MD (aML-MD) models are developed through transfer learning using DFT and multireference data from multiple sources with varying accuracy within the Deep Potential MD framework. Further, the accuracy of the force field is demonstrated by calculating rate constants for the H + HO 2 → H 2 + 3 O 2 reaction using quasi-classical trajectories. We show that the aML-MD model with transfer learning can accurately predict the rate constants while reducing the computational cost by more than five times compared to the use of more expensive quantum chemistry training data sets. Hence, the aML-MD model with transfer learning shows great potential in using multifidelity data to reduce the computational cost involved in generating the training set for these potentials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Effects of composition and growth parameters on phase formation in multicomponent aluminum garnet crystals

The effects of composition on the phase formation of multicomponent garnet crystals grown via directional solidification by the micro-pulling-down method are studied. A relatively wide range of rare-earth (RE) average ionic radii (AIR) is explored by formulating ten compositions from the system (Lu,Y,Ho,Dy,Tb,Gd) 3 Al 5 O 12 . Crystals were grown at either 0.05 or 0.20 mm min -1 . The hypothesis is that multicomponent compounds with large AIR will form secondary phases as the single-RE aluminum garnets formed by larger Tb 3+ or Gd 3+ ; this will result in crystals of poor optical quality. Crystals with large AIR have a central opaque region in optical microscopy images, which is responsible for their reduced transparency compared to crystals with small AIR. Slow pulling rates suppress the formation of the opaque region in crystals with intermediate AIR. Powder and single-crystal X-ray diffraction and electron probe microanalysis results indicate that the opaque region is a perovskite phase. Scanning electron microscopy and energy dispersive spectroscopy measurements reveal eutectic inclusions at the outer surface of the crystals. Finally, the concentration of the eutectic inclusions increases with increasing AIR.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Ho7FeI12 by Materials Project

Ho7FeI12 is trigonal omega-derived structured and crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded to one Fe and five I atoms to form a mixture of distorted edge and corner-sharing HoFeI5 octahedra. The corner-sharing octahedra tilt angles range from 0–9°. The Ho–Fe bond length is 2.59 Å. There are a spread of Ho–I bond distances ranging from 3.08–3.50 Å. In the second Ho site, Ho is bonded to six equivalent I atoms to form edge-sharing HoI6 octahedra. All Ho–I bond lengths are 3.03 Å. Fe is bonded in an octahedral geometry to six equivalent Ho atoms. There are two inequivalent I sites. In the first I site, I is bonded in a distorted T-shaped geometry to three Ho atoms. In the second I site, I is bonded in a 3-coordinate geometry to three equivalent Ho atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on HoZnGe by Materials Project

HoZnGe crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 12-coordinate geometry to six equivalent Zn and six equivalent Ge atoms. All Ho–Zn bond lengths are 2.92 Å. All Ho–Ge bond lengths are 3.25 Å. In the second Ho site, Ho is bonded to six equivalent Ge atoms to form distorted edge-sharing HoGe6 octahedra. All Ho–Ge bond lengths are 2.99 Å. Zn is bonded in a 3-coordinate geometry to three equivalent Ho and three equivalent Ge atoms. All Zn–Ge bond lengths are 2.50 Å. Ge is bonded in a 6-coordinate geometry to six Ho and three equivalent Zn atoms.

36 MATERIALS SCIENCE↗

NASA NTRS1990

New laser materials for laser diode pumping

The potential advantages of laser diode pumped solid state lasers are many with high overall efficiency being the most important. In order to realize these advantages, the solid state laser material needs to be optimized for diode laser pumping and for the particular application. In the case of the Nd laser, materials with a longer upper level radiative lifetime are desirable. This is because the laser diode is fundamentally a cw source, and to obtain high energy storage, a long integration time is necessary. Fluoride crystals are investigated as host materials for the Nd laser and also for IR laser transitions in other rare earths, such as the 2 micron Ho laser and the 3 micron Er laser. The approach is to investigate both known crystals, such as BaY2F8, as well as new crystals such as NaYF8. Emphasis is on the growth and spectroscopy of BaY2F8. These two efforts are parallel efforts. The growth effort is aimed at establishing conditions for obtaining large, high quality boules for laser samples. This requires numerous experimental growth runs; however, from these runs, samples suitable for spectroscopy become available.

Jenssen, H. P.↗

NASA NTRS1993

A process for preparing an assembly of an article and a soluble polyimide which resists dimensional change, delamination, and debonding when exposed to changes in temperature

An assembly of an article and a polyimide is prepared. The assembly resists dimensional change, delamination, or debonding when exposed to changes in temperature. An article is provided. A soluble polyimide resin solution having a low coefficient of thermal expansion (CTE) was prepared by dissolving the polyimide in solvent and adding a metal ion-containing additive to the solution. Examples of the additive are: Ho(OOCCH3), Er(NPPA)3, TmCl3, and Er(C5H7O2)3. The soluble polyimide resin is combined with the article to form the assembly.

Stoakley, Diane M.↗