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At least 1,243 records · Page 69
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on SbH5(O2F3)2 by Materials Project

H2(H3O2)2(H2O2)6(SbF4)4(F2)4 crystallizes in the triclinic P1 space group. The structure is zero-dimensional and consists of four hydrofluoric acid molecules, one hydrogen molecule, two hydrogen peroxide molecules, two water molecules, one H3O2 cluster, and two SbF4 clusters. In the H3O2 cluster, there are three inequivalent H sites. In the first H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.61 Å. In the second H site, H is bonded in a single-bond geometry to one O atom. The H–O bond length is 1.63 Å. In the third H site, H is bonded in a linear geometry to two O atoms. There is one shorter (1.26 Å) and one longer (1.30 Å) H–O bond length. There are two inequivalent O sites. In the first O site, O is bonded in a 2-coordinate geometry to two H atoms. In the second O site, O is bonded in a 1-coordinate geometry to two H atoms. In each SbF4 cluster, Sb is bonded in a 2-coordinate geometry to four F atoms. There are a spread of Sb–F bond distances ranging from 1.77–2.30 Å. There are four inequivalent F sites. In the first F site, F is bonded in a single-bond geometry to one Sb atom. In the second F site, F is bonded in a single-bond geometry to one Sb atom. In the third F site, F is bonded in a single-bond geometry to one Sb atom. In the fourth F site, F is bonded in a single-bond geometry to one Sb atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CuAs12P4S12Br by Materials Project

Cu(As3PS3)4Br crystallizes in the trigonal P31c space group. The structure is zero-dimensional and consists of four cuprum molecules, four hydrobromic acid molecules, and sixteen As3PS3 clusters. In each As3PS3 cluster, there are three inequivalent As+0.33+ sites. In the first As+0.33+ site, As+0.33+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.26 Å. In the second As+0.33+ site, As+0.33+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.26 Å. In the third As+0.33+ site, As+0.33+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.26 Å. P5+ is bonded in a trigonal non-coplanar geometry to three S2- atoms. All P–S bond lengths are 2.10 Å. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a water-like geometry to one As+0.33+ and one P5+ atom. In the second S2- site, S2- is bonded in a water-like geometry to one As+0.33+ and one P5+ atom. In the third S2- site, S2- is bonded in a water-like geometry to one As+0.33+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GeC4NCl3 by Materials Project

C4NGeCl3 is Ammonia-derived structured and crystallizes in the orthorhombic Pnma space group. The structure is zero-dimensional and consists of four trichlorogermane molecules and four C4N clusters. In each C4N cluster, there are three inequivalent C+0.50+ sites. In the first C+0.50+ site, C+0.50+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.69 Å. In the second C+0.50+ site, C+0.50+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.68 Å. In the third C+0.50+ site, C+0.50+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.55 Å. N3- is bonded in a 4-coordinate geometry to four C+0.50+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ZrC8(NCl3)2 by Materials Project

ZrCl6CC4NC3N crystallizes in the monoclinic Cm space group. The structure is zero-dimensional and consists of two 1-azatricyclo[1.1.0.0^{2,4}]butane molecules; two methane molecules; two C4N clusters; and two ZrCl6 clusters. In each C4N cluster, there are three inequivalent C1+ sites. In the first C1+ site, C1+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.52 Å. In the second C1+ site, C1+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.52 Å. In the third C1+ site, C1+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.76 Å. N3- is bonded in a 4-coordinate geometry to four C1+ atoms. In each ZrCl6 cluster, Zr4+ is bonded in an octahedral geometry to six Cl1- atoms. There are a spread of Zr–Cl bond distances ranging from 2.47–2.52 Å. There are four inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Zr4+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Zr4+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Zr4+ atom. In the fourth Cl1- site, Cl1- is bonded in a single-bond geometry to one Zr4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AsC18F17 by Materials Project

C3AsF2(CF)15 crystallizes in the orthorhombic Pbcn space group. The structure is zero-dimensional and consists of sixty fluoromethane molecules and four C3AsF2 clusters. In each C3AsF2 cluster, there are two inequivalent C+1.11+ sites. In the first C+1.11+ site, C+1.11+ is bonded in a single-bond geometry to one As3- atom. The C–As bond length is 1.94 Å. In the second C+1.11+ site, C+1.11+ is bonded in a single-bond geometry to one As3- atom. The C–As bond length is 1.93 Å. As3- is bonded in a trigonal bipyramidal geometry to three C+1.11+ and two equivalent F1- atoms. Both As–F bond lengths are 1.83 Å. F1- is bonded in a single-bond geometry to one As3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CuAs12P4S12Cl by Materials Project

(Cu)2(As3PS3)8Cl2 crystallizes in the trigonal P31c space group. The structure is zero-dimensional and consists of four copper molecules, four hydrochloric acid molecules, and sixteen As3PS3 clusters. In each As3PS3 cluster, there are three inequivalent As+0.33+ sites. In the first As+0.33+ site, As+0.33+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.26 Å. In the second As+0.33+ site, As+0.33+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.26 Å. In the third As+0.33+ site, As+0.33+ is bonded in a single-bond geometry to one S2- atom. The As–S bond length is 2.26 Å. P5+ is bonded in a trigonal non-coplanar geometry to three S2- atoms. There are two shorter (2.10 Å) and one longer (2.11 Å) P–S bond lengths. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a water-like geometry to one As+0.33+ and one P5+ atom. In the second S2- site, S2- is bonded in a water-like geometry to one As+0.33+ and one P5+ atom. In the third S2- site, S2- is bonded in a water-like geometry to one As+0.33+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Ultrafast Correlation Energy Estimator

A virtually no-cost method is proposed that can compute the correlation energies of general, covalently bonded, organic, and inorganic molecules (including conjugated π-electron systems) with a well-defined dominant Lewis structure at the accuracy of 99.5% of the near-exact values determined by the coupled-cluster singles, doubles, and perturbative triples [CCSD(T)] in the complete-basis-set (CBS) limit. This Correlation Energy Per Bond (CEPB) method assigns a partial correlation energy to each bond type (characterized by the identities of the two atoms forming the bond and its integer bond order) and to a lone pair, regardless of the bond length, bond angle, sp-hybridization, π-electron conjugation, ionicity, noncovalent interactions, etc. At its current stage, the method is mainly suitable for near-equilibrium geometries. The correlation energies per bond are determined by a fit to the CCSD(T)/CBS benchmarks. It can neither improve the equilibrium structures nor discern conformers or positional isomers, yet its accuracy for reaction energies rivals that of the second-order Møller–Plesset perturbation theory, which is far more expensive. Its promising performance underscores the possibility that surprisingly compact, chemically intuitive molecular fragments exist into which correlation energies can be partitioned, leading to various ultrafast correlation-energy estimators tailored to different purposes.

Binding energy↗
DOE OSTI2022

Unitary Selective Coupled-Cluster Method

Simulating molecules using the Variational Quantum Eigensolver method is one of the promising applications for NISQ-era quantum computers. Designing an efficient ansatz to represent the electronic wave function is crucial in such simulations. Standard unitary coupled-cluster with singles and doubles (UCCSD) ansatz tends to have a large number of insignificant terms that do not lower the energy of the system. In this work, we present a unitary selective coupled-cluster method, a way to construct a unitary coupled-cluster ansatz iteratively using a selection procedure with excitations up to fourth order. This approach uses the electronic Hamiltonian matrix elements and the amplitudes for excitations already present in the ansatz to find the important excitations of higher order and to add them to the ansatz. The important feature of the method is that it systematically reduces the energy error with increasing ansatz size for a set of test molecules. {The main advantage of the proposed method is that the effort to increase the ansatz does not require any additional measurements on a quantum computer.}

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Atomically Dispersed Copper Sites in a Metal–Organic Framework for Reduction of Nitrogen Dioxide

Metal-organic framework (MOF) materials provide an excellent platform to fabricate single-atom catalysts due to their structural diversity, intrinsic porosity, and designable functionality. However, the unambiguous identification of atomically dispersed metal sites and the elucidation of their role in catalysis are challenging due to limited methods of characterization and lack of direct structural information. Here, we report a comprehensive investigation of the structure and the role of atomically dispersed copper sites in UiO-66 for the catalytic reduction of NO 2 at ambient temperature. The atomic dispersion of copper sites on UiO-66 is confirmed by high-angle annular dark-field scanning transmission electron microscopy, electron paramagnetic resonance spectroscopy, and inelastic neutron scattering, and their location is identified by neutron powder diffraction and solid-state nuclear magnetic resonance spectroscopy. The Cu/UiO-66 catalyst exhibits superior catalytic performance for the reduction of NO 2 at 25 °C without the use of reductants. A selectivity of 88% for the formation of N2 at a 97% conversion of NO 2 with a lifetime of >50 h and an unprecedented turnover frequency of 6.1 h-1 is achieved under nonthermal plasma activation. In situ and operando infrared, solid-state NMR, and EPR spectroscopy reveal the critical role of copper sites in the adsorption and activation of NO 2 molecules, with the formation of {Cu(I)···NO} and {Cu···NO 2 } adducts promoting the conversion of NO 2 to N 2 . This study will inspire the further design and study of new efficient single-atom catalysts for NO 2 abatement via detailed unravelling of their role in catalysis.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Mechanistic Advantages of Organotin Molecular EUV Photoresists

Here, extreme ultraviolet (EUV)-induced radiation exposure chemistry in organotin-oxo systems, represented by the archetypal [(R-Sn) 12 O 14 (OH) 6 ](A) 2 cage, has been investigated with density functional theory. Upholding existing experimental evidence of Sn-C cleavage-dominant chemistry, computations have revealed that either electron attachment or ionization can single-handedly trigger tin-carbon bond cleavage, partially explaining the current EUV sensitivity advantage of metal oxide systems. We have revealed that tin atoms at different parts of the molecule react differently to ionization and electron attachment and have identified such selectivity as a result of local coordination chemistry instead of the macro geometry of the molecule. An ionization-deprotonation pathway has also been identified to explain the observed evolution of an anion conjugate acid upon exposure and anion mass dependence in resist sensitivity.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2025

Acidities of MgO surface sites: implications for the formation mechanism of Mg(OH) 2

The hydroxylation of periclase (MgO) to brucite (Mg(OH) 2 ) is thought to be an important intermediate step when using MgO to capture CO 2 from the atmosphere. However, the mechanism of hydroxylation of MgO to form Mg(OH) 2 is poorly understood. In this work, we used atomic-scale density functional tight binding simulations coupled with the metadynamics rare event method to analyze the surface chemistry of MgO and the acid dissociation equilibrium constants (pK a ) of its surface sites. The method and parameters were validated by calculating the pK a for hydroxylation of the first shell water bound to aqueous Mg 2+ ion. The pK a value derived using a probabilistic method was 12.3, which is in fair agreement with the accepted value of 11.4, with the difference between them equal to a ∼5 kJ mol −1 error in the calculations. We then extended these pK a calculations to probe the hydroxylation reactions of the surface sites of the MgO(100)–water interface, arriving at pK a s of 5.4 to deprotonate terminal water molecules bound to the surface magnesium sites (η-OH 2 or 〉MgOH 2 ), and 13.9 to deprotonate hydroxylated bridging oxygen sites (μ 5 -oxo or 〉O). Hydroxide (OH − ) adsorption on the surface was also probed and found to be less thermodynamically favorable than deprotonation of the terminal water molecule. The plausibility of the computed pK a s was verified using an activity-based speciation model and compared to pH measurements of water equilibrated with MgO nanoparticles and single crystals. The model predicted a solution pH of 7.1 when surface sites buffered and the pH of 12.0 when MgO dissolution dominated. These are close to the experimental initial solution pHs of 7–7.5 and the long term pHs of ∼10.5. The similarity suggests that the calculated pK a values from the DFTB+/metadynamics simulations are plausible and that these methods can be a useful tool to probe reaction mechanisms involving covalent bonds.

Adapa, Sai Krishna Reddy [Oak Ridge National Labor↗
DOE OSTI2021

Confinement effects on the solvation structure of solvated alkaline metal cations in a single-digit 1T-MoS 2 nanochannel: A first-principles study

Confinement plays an important role in determining ion transport in porous materials, which, in turn, may influence the performance of many energy storage and desalination devices. In this work, we combined density functional theory (DFT) with an implicit solvation model and ab initio molecular dynamics (AIMD) to investigate the effects of nanoconfinement on several solvated alkaline metal cations in a single-digit 1T-MoS 2 nanochannel. Our DFT calculations with a solvation model indicated that cations with stronger hydration energy introduce a higher number of co-intercalated water molecules into the channel, consistent with early experimental observation obtained for MXene (2D transition metal carbide) channels. The predicted optimal water numbers for the cations were then used for AIMD simulations that explicitly include the effects of the solvent. When compared with the cations in bulk solution, our simulations showed that the hydration structure and coordination number (CN) of the solvated cations confined in the MoS 2 channel can be significantly altered. Further, we found that larger cations with weaker hydration energy (K + , Rb + , and Cs + ) exhibited a distinctive CN decrease under confinement, while smaller cations (Li + and Na + ) retained a similar hydration shell as in the bulk solution. More specifically, the hydration shell of large cations (K + , Rb + , and Cs + ) in MoS 2 showed similar features of the coordination angle to the bulk, which suggests the partially broken hydration shell with no geometry change under confinement. Our simulations provided insights into the change of the hydration structure of alkaline metal cations under confinement, which may have important implications on their transport in the 1T-MoS 2 channel.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PI3 by Materials Project

PI3 is Upper Bainite structured and crystallizes in the hexagonal P6_3 space group. The structure is zero-dimensional and consists of two phosphorus triiodide molecules. P3+ is bonded in a trigonal non-coplanar geometry to three equivalent I1- atoms. All P–I bond lengths are 2.49 Å. I1- is bonded in a single-bond geometry to one P3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on B9H11C2 by Materials Project

B13C4H17(BH)5 crystallizes in the monoclinic C2/c space group. The structure is zero-dimensional and consists of forty boranediylradical molecules and eight B13C4H17 clusters. In each B13C4H17 cluster, there are thirteen inequivalent B+0.33- sites. In the first B+0.33- site, B+0.33- is bonded in a distorted single-bond geometry to one B+0.33- and one H1+ atom. The B–B bond length is 1.70 Å. The B–H bond length is 1.34 Å. In the second B+0.33- site, B+0.33- is bonded in a distorted bent 120 degrees geometry to one C4- and one H1+ atom. The B–C bond length is 1.52 Å. The B–H bond length is 1.19 Å. In the third B+0.33- site, B+0.33- is bonded in a 3-coordinate geometry to two C4- and one H1+ atom. There is one shorter (1.69 Å) and one longer (1.71 Å) B–C bond length. The B–H bond length is 1.19 Å. In the fourth B+0.33- site, B+0.33- is bonded in a distorted bent 120 degrees geometry to one C4- and one H1+ atom. The B–C bond length is 1.66 Å. The B–H bond length is 1.19 Å. In the fifth B+0.33- site, B+0.33- is bonded in a distorted bent 120 degrees geometry to one C4- and one H1+ atom. The B–C bond length is 1.70 Å. The B–H bond length is 1.19 Å. In the sixth B+0.33- site, B+0.33- is bonded in a single-bond geometry to one B+0.33- and one H1+ atom. The B–B bond length is 1.78 Å. The B–H bond length is 1.19 Å. In the seventh B+0.33- site, B+0.33- is bonded in a distorted bent 120 degrees geometry to one B+0.33-, one C4-, and one H1+ atom. The B–B bond length is 1.79 Å. The B–C bond length is 1.69 Å. The B–H bond length is 1.19 Å. In the eighth B+0.33- site, B+0.33- is bonded in a 3-coordinate geometry to two C4- and one H1+ atom. Both B–C bond lengths are 1.72 Å. The B–H bond length is 1.19 Å. In the ninth B+0.33- site, B+0.33- is bonded in a distorted bent 120 degrees geometry to one C4- and one H1+ atom. The B–C bond length is 1.70 Å. The B–H bond length is 1.19 Å. In the tenth B+0.33- site, B+0.33- is bonded in a distorted bent 120 degrees geometry to one B+0.33-, one C4-, and one H1+ atom. The B–B bond length is 1.79 Å. The B–C bond length is 1.69 Å. The B–H bond length is 1.19 Å. In the eleventh B+0.33- site, B+0.33- is bonded in a 6-coordinate geometry to four B+0.33- and two C4- atoms. Both B–C bond lengths are 1.73 Å. In the twelfth B+0.33- site, B+0.33- is bonded in a distorted trigonal non-coplanar geometry to three H1+ atoms. There is one shorter (1.19 Å) and two longer (1.33 Å) B–H bond length. In the thirteenth B+0.33- site, B+0.33- is bonded in a 3-coordinate geometry to one C4- and two H1+ atoms. The B–C bond length is 1.75 Å. There is one shorter (1.19 Å) and one longer (1.33 Å) B–H bond length. There are four inequivalent C4- sites. In the first C4- site, C4- is bonded in a 2-coordinate geometry to two B+0.33-, one C4-, and one H1+ atom. The C–C bond length is 1.46 Å. The C–H bond length is 1.09 Å. In the second C4- site, C4- is bonded in a 1-coordinate geometry to three B+0.33-, one C4-, and one H1+ atom. The C–H bond length is 1.09 Å. In the third C4- site, C4- is bonded in a 1-coordinate geometry to four B+0.33- and one H1+ atom. The C–H bond length is 1.09 Å. In the fourth C4- site, C4- is bonded in a 1-coordinate geometry to four B+0.33- and one H1+ atom. The C–H bond length is 1.09 Å. There are sixteen inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one B+0.33- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one B+0.33- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one B+0.33- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one B+0.33- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one B+0.33- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one B+0.33- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one B+0.33- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one B+0.33- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one B+0.33- atom. In the twelfth H1+ site, H1+ is bonded in an L-shaped geometry to two B+0.33- atoms. In the thirteenth H1+ site, H1+ is bonded in an L-shaped geometry to two B+0.33- atoms. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one B+0.33- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom. In the sixteenth H1+ site, H1+ is bonded in a single-bond geometry to one C4- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on H3N by Materials Project

NH3 is Ammonia structured and crystallizes in the cubic P2_13 space group. The structure is zero-dimensional and consists of four ammonia molecules. N3- is bonded in a trigonal non-coplanar geometry to three equivalent H1+ atoms. All N–H bond lengths are 1.03 Å. H1+ is bonded in a single-bond geometry to one N3- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SiCl2 by Materials Project

SiCl2 crystallizes in the orthorhombic P2_12_12_1 space group. The structure is zero-dimensional and consists of four dichlorosilane molecules. Si is bonded in a distorted water-like geometry to two equivalent Cl atoms. Both Si–Cl bond lengths are 2.06 Å. Cl is bonded in a single-bond geometry to one Si atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SiBr2 by Materials Project

SiBr2 crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of twenty dibromosilane molecules. Si4- is bonded in a distorted water-like geometry to two equivalent Br2+ atoms. Both Si–Br bond lengths are 2.23 Å. Br2+ is bonded in a single-bond geometry to one Si4- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BS2N2OF7 by Materials Project

BF3NSF2NS(O)F2 crystallizes in the monoclinic P2_1/m space group. The structure is zero-dimensional and consists of two boron trifluoride molecules and two NSF2NS(O)F2 clusters. In each NSF2NS(O)F2 cluster, there are two inequivalent N5+ sites. In the first N5+ site, N5+ is bonded in a single-bond geometry to one S2- atom. The N–S bond length is 1.42 Å. In the second N5+ site, N5+ is bonded in a bent 120 degrees geometry to two S2- atoms. There is one shorter (1.53 Å) and one longer (1.59 Å) N–S bond length. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded to one N5+, one O2-, and two equivalent F1- atoms to form distorted corner-sharing SNOF2 tetrahedra. The S–O bond length is 1.41 Å. Both S–F bond lengths are 1.55 Å. In the second S2- site, S2- is bonded to two N5+ and two equivalent F1- atoms to form distorted corner-sharing SN2F2 tetrahedra. Both S–F bond lengths are 1.57 Å. O2- is bonded in a single-bond geometry to one S2- atom. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one S2- atom. In the second F1- site, F1- is bonded in a single-bond geometry to one S2- atom.

36 MATERIALS SCIENCE↗