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At least 163 records · Page 9

Materials Data on Ho(Mo3Se4)2 by Materials Project

HoMo6Se8 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. Ho3+ is bonded in a body-centered cubic geometry to eight Se2- atoms. There are two shorter (2.81 Å) and six longer (3.10 Å) Ho–Se bond lengths. Mo+2.17+ is bonded to five Se2- atoms to form a mixture of edge and corner-sharing MoSe5 square pyramids. There are a spread of Mo–Se bond distances ranging from 2.54–2.75 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 1-coordinate geometry to one Ho3+ and three equivalent Mo+2.17+ atoms. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to one Ho3+ and four equivalent Mo+2.17+ atoms.

36 MATERIALS SCIENCE↗

Inefficient intramolecular vibrational energy redistribution for the H + HO2 reaction and negative internal energy dependence for its rate constant

Quasiclassical trajectories (QCT) and newly constructed global potential energy surfaces are used to compute thermal and nonthermal rate constants for the H + HO 2 reaction. The thermal QCTs rate constants are up to 50% smaller than transition state theory (TST) rate constants based on the same level of electronic structure theory. This reduction is demonstrated to result from inefficient intramolecular vibrational energy redistribution (IVR) in the transient H 2 O 2 well, with a significant fraction of trajectories that reach the H 2 O 2 well promptly dissociating back to reactants instead of via the heavily statistically favored 2OH channel. The nonstatistical reduction factor, κ IVR , that quantifies this effect is shown to increase in importance with temperature, with κ IVR = 0.81 at 300 K and 0.47 at 2500 K. Finally, we show that inefficient IVR causes H + HO 2 rate constants mediated by H 2 O 2 to depend inversely on the initial vibrational excitation of HO 2 .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

Materials Data on Ho(Mo3S4)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗

Materials Data on Ho(BC)2 by Materials Project

HoB2C2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Ho is bonded in a 8-coordinate geometry to eight equivalent B and eight equivalent C atoms. All Ho–B bond lengths are 2.73 Å. All Ho–C bond lengths are 2.67 Å. B is bonded in a distorted trigonal planar geometry to four equivalent Ho and three equivalent C atoms. There is one shorter (1.52 Å) and two longer (1.60 Å) B–C bond length. C is bonded in a 3-coordinate geometry to four equivalent Ho and three equivalent B atoms.

36 MATERIALS SCIENCE↗

Materials Data on Ho(FeGe)2 by Materials Project

HoFe2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho is bonded in a 8-coordinate geometry to eight equivalent Fe and eight equivalent Ge atoms. All Ho–Fe bond lengths are 3.32 Å. All Ho–Ge bond lengths are 3.05 Å. Fe is bonded to four equivalent Ho and four equivalent Ge atoms to form a mixture of edge, corner, and face-sharing FeHo4Ge4 tetrahedra. All Fe–Ge bond lengths are 2.43 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Ho, four equivalent Fe, and one Ge atom. The Ge–Ge bond length is 2.51 Å.

36 MATERIALS SCIENCE↗

Materials Data on Ho(NiGe)2 by Materials Project

HoNi2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho is bonded in a 8-coordinate geometry to eight equivalent Ni and eight equivalent Ge atoms. All Ho–Ni bond lengths are 3.18 Å. All Ho–Ge bond lengths are 3.13 Å. Ni is bonded in a 4-coordinate geometry to four equivalent Ho and four equivalent Ge atoms. All Ni–Ge bond lengths are 2.35 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Ho, four equivalent Ni, and one Ge atom. The Ge–Ge bond length is 2.51 Å.

36 MATERIALS SCIENCE↗

Materials Data on Ho(CoGe)2 by Materials Project

HoCo2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho is bonded in a 8-coordinate geometry to eight equivalent Co and eight equivalent Ge atoms. All Ho–Co bond lengths are 3.21 Å. All Ho–Ge bond lengths are 3.08 Å. Co is bonded to four equivalent Ho and four equivalent Ge atoms to form a mixture of distorted corner, edge, and face-sharing CoHo4Ge4 tetrahedra. All Co–Ge bond lengths are 2.33 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Ho, four equivalent Co, and one Ge atom. The Ge–Ge bond length is 2.57 Å.

36 MATERIALS SCIENCE↗

Materials Data on Ho(CuGe)2 by Materials Project

HoCu2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho is bonded in a 8-coordinate geometry to eight equivalent Cu and eight equivalent Ge atoms. All Ho–Cu bond lengths are 3.28 Å. All Ho–Ge bond lengths are 3.11 Å. Cu is bonded to four equivalent Ho and four equivalent Ge atoms to form a mixture of distorted face, edge, and corner-sharing CuHo4Ge4 tetrahedra. All Cu–Ge bond lengths are 2.43 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Ho, four equivalent Cu, and one Ge atom. The Ge–Ge bond length is 2.46 Å.

36 MATERIALS SCIENCE↗

Materials Data on Ho(GePd)2 by Materials Project

HoPd2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho is bonded in a 8-coordinate geometry to eight equivalent Pd and eight equivalent Ge atoms. All Ho–Pd bond lengths are 3.32 Å. All Ho–Ge bond lengths are 3.25 Å. Pd is bonded in a 4-coordinate geometry to four equivalent Ho and four equivalent Ge atoms. All Pd–Ge bond lengths are 2.52 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Ho, four equivalent Pd, and one Ge atom. The Ge–Ge bond length is 2.43 Å.

36 MATERIALS SCIENCE↗

Materials Data on Ho(MnGe)2 by Materials Project

HoMn2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho is bonded in a 8-coordinate geometry to eight equivalent Ge atoms. All Ho–Ge bond lengths are 3.06 Å. Mn is bonded to four equivalent Ge atoms to form a mixture of corner and edge-sharing MnGe4 tetrahedra. All Mn–Ge bond lengths are 2.43 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Ho, four equivalent Mn, and one Ge atom. The Ge–Ge bond length is 2.57 Å.

36 MATERIALS SCIENCE↗

Materials Data on Ho(Fe5Si)2 by Materials Project

HoFe10Si2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Ho is bonded in a 12-coordinate geometry to sixteen Fe and four equivalent Si atoms. There are a spread of Ho–Fe bond distances ranging from 2.93–3.18 Å. All Ho–Si bond lengths are 3.09 Å. There are four inequivalent Fe sites. In the first Fe site, Fe is bonded in a 10-coordinate geometry to one Ho, eleven Fe, and two equivalent Si atoms. There are a spread of Fe–Fe bond distances ranging from 2.33–2.91 Å. Both Fe–Si bond lengths are 2.60 Å. In the second Fe site, Fe is bonded in a 10-coordinate geometry to one Ho, eleven Fe, and two equivalent Si atoms. There are a spread of Fe–Fe bond distances ranging from 2.41–2.67 Å. Both Fe–Si bond lengths are 2.53 Å. In the third Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Ho, eight Fe, and two equivalent Si atoms. All Fe–Fe bond lengths are 2.44 Å. Both Fe–Si bond lengths are 2.61 Å. In the fourth Fe site, Fe is bonded to two equivalent Ho, eight Fe, and two equivalent Si atoms to form distorted FeHo2Fe8Si2 cuboctahedra that share corners with four equivalent SiHo2Fe10 cuboctahedra, corners with ten equivalent FeHo2Fe8Si2 cuboctahedra, edges with two equivalent SiHo2Fe10 cuboctahedra, edges with four equivalent FeHo2Fe8Si2 cuboctahedra, faces with four equivalent SiHo2Fe10 cuboctahedra, and faces with six equivalent FeHo2Fe8Si2 cuboctahedra. Both Fe–Fe bond lengths are 2.38 Å. Both Fe–Si bond lengths are 2.39 Å. Si is bonded to two equivalent Ho and ten Fe atoms to form distorted SiHo2Fe10 cuboctahedra that share corners with six equivalent SiHo2Fe10 cuboctahedra, corners with eight equivalent FeHo2Fe8Si2 cuboctahedra, edges with three equivalent SiHo2Fe10 cuboctahedra, edges with four equivalent FeHo2Fe8Si2 cuboctahedra, a faceface with one SiHo2Fe10 cuboctahedra, and faces with eight equivalent FeHo2Fe8Si2 cuboctahedra.

36 MATERIALS SCIENCE↗

Materials Data on Ho(Fe2Ge)2 by Materials Project

HoFe4Ge2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Ho is bonded in a 6-coordinate geometry to twelve equivalent Fe and six equivalent Ge atoms. There are four shorter (3.17 Å) and eight longer (3.27 Å) Ho–Fe bond lengths. There are two shorter (2.91 Å) and four longer (2.94 Å) Ho–Ge bond lengths. Fe is bonded in a 3-coordinate geometry to three equivalent Ho and three equivalent Ge atoms. There are one shorter (2.43 Å) and two longer (2.44 Å) Fe–Ge bond lengths. Ge is bonded in a 9-coordinate geometry to three equivalent Ho and six equivalent Fe atoms.

36 MATERIALS SCIENCE↗

Materials Data on Ho(CrSi)2 by Materials Project

HoCr2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho3+ is bonded in a body-centered cubic geometry to eight equivalent Si4- atoms. All Ho–Si bond lengths are 2.98 Å. Cr+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing CrSi4 tetrahedra. All Cr–Si bond lengths are 2.40 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Ho3+, four equivalent Cr+2.50+, and one Si4- atom. The Si–Si bond length is 2.45 Å.

36 MATERIALS SCIENCE↗

Materials Data on Ho(CoB)2 by Materials Project

HoCo2B2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho3+ is bonded in a body-centered cubic geometry to eight equivalent B3- atoms. All Ho–B bond lengths are 2.87 Å. Co+1.50+ is bonded to four equivalent B3- atoms to form a mixture of edge and corner-sharing CoB4 tetrahedra. All Co–B bond lengths are 2.01 Å. B3- is bonded in a 4-coordinate geometry to four equivalent Ho3+ and four equivalent Co+1.50+ atoms.

36 MATERIALS SCIENCE↗

Materials Data on Ho(FeSi)2 by Materials Project

HoFe2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Ho–Si bond lengths are 3.07 Å. Fe+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing FeSi4 tetrahedra. All Fe–Si bond lengths are 2.26 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Ho3+, four equivalent Fe+2.50+, and one Si4- atom. The Si–Si bond length is 2.54 Å.

36 MATERIALS SCIENCE↗

Materials Data on Ho(CuSi)2 by Materials Project

HoCu2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Ho–Si bond lengths are 3.03 Å. Cu+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing CuSi4 tetrahedra. All Cu–Si bond lengths are 2.38 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Ho3+, four equivalent Cu+2.50+, and one Si4- atom. The Si–Si bond length is 2.34 Å.

36 MATERIALS SCIENCE↗

Materials Data on Ho(CoSi)2 by Materials Project

HoCo2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho3+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All Ho–Si bond lengths are 3.01 Å. Co+2.50+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing CoSi4 tetrahedra. All Co–Si bond lengths are 2.27 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent Ho3+, four equivalent Co+2.50+, and one Si4- atom. The Si–Si bond length is 2.49 Å.

36 MATERIALS SCIENCE↗

Kinetics of low temperature plasma assisted NH 3 /H 2 oxidation in a nanosecond-pulsed discharge

Ammonia (NH 3 ) has been widely recognized as one of the carbon-neutral fuels. However, ammonia combustion suffers low reactivity and high N 2 O/NO x emissions. Here, to overcome these issues, this work reports plasma assisted NH 3 /H 2 oxidation and unveils the kinetics of fuel oxidation and N 2 O/NO x formation by combining time-resolved laser diagnostics with plasma modeling. Firstly, we found that the NH 3 consumption is promoted with a H 2 blending ratio of 0.3, due to enhancements of H and OH formation by plasma assisted H 2 dissociation. Secondly, at a high reduced electric field, when the H 2 blending ratio increases, the NH 3 oxidation is promoted due to both the HO 2 formation and strong NO kinetic enhancement via NO-HO 2 and NO 2 -H pathways. In the meantime, it is shown that the NO mole fraction also increases with H 2 blending ratio, because the NO formation is enhanced via N( 2 D)-O 2 pathways, and the DeNO x chemistry is weakened with less NH 2 production. By contrast, at a lower reduced electric field, when the H 2 blending ratio increases, the decreased N( 2 D) formation does not produce enough NO to replenish the NO formation drop caused by lower NH 3 concentration. Thirdly, the reduced electric field non-monotonically affects fuel consumption and N 2 O/NO x formation by manipulating electron energy deposition pathways. The NH 3 consumption is maximized with an optimal reduced electric field where N 2 * excitation and O 2 dissociation are most efficient. When the reduced electric field deviates from its optimum, the NH 3 consumption decreases due to the discharge energy deposition to either vibrational excitation or dissociation of N 2 . The N 2 O/NO x emissions governed by the NH 3 oxidation follow the above NH 3 consumption trend.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗