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DOE OSTI2020

Stepwise Assembly of Turn‐on Fluorescence Sensors in Multicomponent Metal–Organic Frameworks for in Vitro Cyanide Detection

Abstract The controlled synthesis of multicomponent metal–organic frameworks (MOFs) allows for the precise placement of multiple cooperative functional groups within a framework, leading to emergent synergistic effects. Herein, we demonstrate that turn‐on fluorescence sensors can be assembled by combining a fluorophore and a recognition moiety within a complex cavity of a multicomponent MOF. An anthracene‐based fluorescent linker and a hemicyanine‐containing CN − ‐responsive linker were sequentially installed into the lattice of PCN‐700. The selective binding of CN − to hemicyanine inhibited the energy transfer between the two moieties, resulting in a fluorescence turn‐on effect. Taking advantage of the high tunability of the MOF platform, the ratio between anthracene and the hemicyanine moiety could be fine‐tuned in order to maximize the sensitivity of the overall framework. The optimized MOF‐sensor had a CN − ‐detection limit of 0.05 μ m , which is much lower than traditional CN − fluorescent sensors (about 0.2 μ m ).

Li, Jialuo↗

DOE OSTI2025

Photocatalytic Activity and Stability of Carbon Nitride‐Pyrite Composites

Abstract In photocatalysis, the photoabsorber plays a crucial role in the reaction. The most important parameters are stability, cost and optical band gap. In this work, a prominent class of absorbers, namely carbon nitrides (CN), has been investigated. In the literature, CN is most often described as stable, although photodegradation has been observed. In order to retain the beneficial properties of CN while improving stability, a crystalline phase poly(triazine imide) (PTI) of carbon nitride was investigated and compared to polymeric CN in photocatalytic hydrogen generation experiments. In order to improve the charge separation for the photoinduced hydrogen evolution reaction, pyrite (FeS 2 ) was used as a surface co‐catalyst with a loading of 1, 5 and 10 wt %. At the same time, any photodegradation products in solution were investigated by ion chromatography. Interestingly, PTI shows hardly any photocorrosion compared to defective carbon nitride, indicating its higher photostability in hydrogen evolution experiments. However, FeS 2 produces ammonium as a degradation product when synthesised from nitrogen‐containing precursors. When made from nitrogen‐free precursors, FeS 2 together with photostable PTI releases little ammonia, making it a photostable, earth‐abundant composite for photocatalytic hydrogen generation.

Kaulbersch, Julian [University of Bayreuth 95440 B↗

DOE OSTI2024

Enhanced Carbon‐Carbon Coupling at Interfaces with Abrupt Coordination Number Changes

Abstract Cu‐catalyzed electrochemical CO 2 reduction reaction (CO 2 RR) produces multi‐carbon (C 2+ ) chemicals with considerable selectivities and activities, yet required high overpotentials impede its practical application. Here, we design interfaces with abrupt coordination number (CN) changes that greatly reduce the applied potential for achieving high C 2+ Faradaic efficiency (FE). Encouraged by the mechanistic finding that the coupling between *CO and *CO(H) is the most probable C−C bond formation path, we use Cu 2 O‐ and Cu‐phthalocyanine‐derived Cu (OD−Cu and PD−Cu) to build the interface. Using operando X‐ray absorption spectroscopy (XAS), we find that the Cu CN of OD−Cu is ~11, favoring CO* adsorption, while the PD−Cu has a COH*‐favorable CN of ~4. Operando Raman spectroscopy revealed that the interfaces with abrupt CN changes promote *OCCOH formation. As a result, the designed catalyst achieves a C 2+ FE of 85±2 % at 220 mA cm −2 in a zero‐gap CO 2 electrolyzer. An improvement of C 2+ FE by 3 times is confirmed at the low potential regime where the current density is 60–140 mA cm −2 , compared to bare OD−Cu. We report a 45‐h stable CO 2 RR operation at 220 mA cm −2 , producing a C 2+ product FE of ~80 %.

Chemistry↗

DOE OSTI2022

High Sensitivity of Non–Fullerene Organic Solar Cells Morphology and Performance to a Processing Additive

Although solvent additives are used to optimize device performance in many novel non-fullerene acceptor (NFA) organic solar cells (OSCs), the effect of processing additives on OSC structures and functionalities can be difficult to predict. Here, two polymer-NFA OSCs with highly sensitive device performance and morphology to the most prevalent solvent additive chloronaphthalene (CN) are presented. Devices with 1% CN additive are found to nearly double device efficiencies to 10%. However, additive concentrations even slightly above optimum significantly hinder device performance due to formation of undesirable morphologies. A comprehensive analysis of device nanostructure shows that CN is critical to increasing crystallinity and optimizing phase separation up to the optimal concentration for suppressing charge recombination and maximizing performance. Here, domain purity and crystallinity are highly correlated with photocurrent and fill factors. However, this effect is in competition with uncontrolled crystallization of NFAs that occur at CN concentrations slightly above optimal. This study highlights how slight variations of solvent additives can impart detrimental effects to morphology and device performance of NFA OSCs. Furthermore, successful scale-up processing of NFA-based OSCs will require extreme formulation control, a tuned NFA structure that resists runaway crystallization, or alternative methods such as additive-free fabrication.

14 SOLAR ENERGY↗

DOE OSTI2021

Transition state stabilization depends on solvent identity, pore size, and hydrophilicity for epoxidations in zeolites

Ti-silicates activate H 2 O 2 to form Ti-hydroperoxo and Ti-peroxo intermediates that can react with alkenes to form epoxide products. Comparisons of kinetics for 1-octene epoxidation with H 2 O 2 on Ti-BEA and Ti-MFI catalysts with different hydrophilicities in methanol (CH 3 OH) or acetonitrile (CH 3 CN) solvents show the significance of the solvent for stabilizing catalytically-relevant species and the complex interdependencies between solvent, catalyst topology, and hydrophilicity. Epoxidation turnover rates are higher in CH 3 CN than CH 3 OH for Ti-BEA, but the opposite trend is observed for Ti-MFI. Ti-silicates with greater silanol densities, however, give greater epoxidation turnover rates than their hydrophobic counterparts in both solvents. Kinetic, spectroscopic, and thermodynamic analyses show that differences in turnover rates mainly arise from changes in the stabilization of reactive surface species by solvent mediated interactions, because the mechanism of the reaction and stability of the fluid-phase reactants remain similar in CH 3 CN and CH 3 OH. Specifically, apparent activation free energy values ($ΔG^{‡}_{App}$) indicate that surface intermediates responsible for alkene epoxidation are stabilized to a greater extent in CH 3 CN on Ti-BEA and in CH 3 OH on Ti-MFI. Hydrophilic Ti-silicates present lower ($ΔG^{‡}_{App}$) values regardless of solvent identity, which suggests that these differences correspond to the number of hydrogen-bonding solvent molecules found near reactive species bound to Ti active sites. Finally, taken together, these findings demonstrate the role of solvent molecules in allowing reactive intermediates to recognize the properties of active sites beyond the length-scale of covalent bonds, which carry implications for epoxidation but also other reactions within solvent-filled pores of microporous materials.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2024

Two Spacers, One Perovskite: Integrating Ruddlesden–Popper and Dion–Jacobson Halide Perovskites

Hybrid organic–inorganic perovskites are a rapidly developing class of materials due to their desirable properties for optoelectronic applications such as their ease of synthesis, solution-processable film formation, tunable band gap, strong photoluminescence, good charge carrier mobilities, and high defect tolerance. Here, we present a novel 2D perovskite motif that seamlessly integrates the structural elements from both Ruddlesden–Popper and Dion–Jacobson halide perovskites. We demonstrate the incorporation of two different organic spacer cations in an ordered manner in 5 novel 2D perovskite iodide materials. Both a cyclic diammonium cation 3-(aminomethyl)piperidinium (3AMP) and a linear alkyl monoammonium cation (Cn = C n H 2n+4 N, n = 4–8) are present in distinct alternating layers, making the new series (Cn) 2 (3AMP)[PbI 4 ] 2 . The crystallization of these materials was optimized through careful temperature control to obtain precise crystal structures via single-crystal X-ray diffraction (XRD) which confirmed the presence of the two cations in distinct layers. The influence of the two spacers on optical properties including the band gaps and photoluminescence spectra are found to more closely resemble (3AMP)PbI 4 than (Cn) 2 PbI 4 , which can be attributed to the amount of distortion imposed by the 3AMP spacer on the lead iodide layers. The findings are supported by density functional theory calculations. The strong photoelectric response of solution-processed thin films shows the potential of these materials in photodetectors or photovoltaics. This unprecedented amalgamation of RP–DJ in (Cn) 2 (3AMP)[PbI 4 ] 2 in a structurally ordered fashion suggests a potential vastly underexplored phase space of 2D perovskites in which there are chemically different spacers in distinct layers of the structure, providing an additional parameter to tune perovskite properties.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2025

Measurement of Spray Chamber Ignition Delay and Cetane Numbers for Aviation Turbine Fuels

Experiments using pure compounds, National Jet Fuels Combustion Program (NJFCP) test fuels, and commercial jet fuels were conducted to demonstrate the equivalence of the indicated cetane number (ICN) and derived cetane number (DCN) for jet fuels. The calibrated range for ICN was also extended to lower cetane number (CN) values (5 to 35) to allow CN quantification for jet fuel synthetic blending components (SBCs) with low CN. ICN and DCN were shown to be highly correlated for values above about 30. This study presents the most comprehensive comparison of these two methods published to date. Because of the importance of low-volume test methods for early-stage SBC production process development, we demonstrated that ICN and DCN can be accurately measured with 15 mL of fuel, well below 40 to 100 mL required by standard methods. ICN or DCN is important for jet fuels because fuels with lower CN are more prone to lean blowout (LBO), an undesirable operational failure in a jet engine. Comparing data on a fuel-to-air ratio (Φ) at LBO for the NJFCP fuels shows similar linear correlations for ICN and DCN. Ignition delay measurements at lower-pressure and higher-temperature conditions may be more directly relevant to LBO. At 675 °C, 0.5 MPa, and a global Φ of roughly 0.68, ignition delay time correlations to LBO were similar to those produced from DCN and ICN. A much weaker correlation was obtained with a global Φ value of 0.34.

09 BIOMASS FUELS↗

DOE OSTI2020

Trivalent f-Element Squarates, Squarate-Oxalates, and Cationic Materials, and the Determination of the Nine-Coordinate Ionic Radius of Cf(III)

The synthesis, structure, and solid-state UV–vis–NIR spectroscopy of four new f-element squarates, M 2 (C 4 O 4 ) 3 (H 2 O) 4 (M = Eu, Am, Cf) and Sm(C 4 O 4 )(C 4 O 3 OH)(H 2 O) 2 ·0.5H 2 O, four new cationic lanthanide squarate chlorides, [M 4 (C 4 O 4 ) 5 (H 2 O) 12 ]Cl 2 ·5H 2 O (M = Eu, Dy, Ho Er), and two new actinide squarate oxalates, M 2 (C 4 O 4 ) 2 (C 2 O 4 )(H 2 O) 4 (M = Am, Cf), are presented. All of the metal centers are trivalent. Single-crystal X-ray diffraction analysis reveals that M 2 (C 4 O 4 ) 3 (H 2 O) 4 and Sm(C 4 O 4 )(C 4 O 3 OH)(H 2 O) 2 ·0.5H 2 O have a two-dimensional sheet structure constructed from MO 7 (H 2 O) 2 monocapped square-antiprismatic (coordination number (CN) = 9) metal centers and SmO 6 (H 2 O) 2 square-antiprismatic (CN = 8) metal centers, respectively, whereas M 2 (C 4 O 4 ) 2 (C 2 O 4 )(H 2 O) 4 have a three-dimensional (3D) structure constructed from MO 7 (H 2 O) 2 monocapped square-antiprismatic (CN = 9) metal centers. Additionally, the cationic framework materials [M 4 (C 4 O 4 ) 5 (H 2 O) 12 ]Cl 2 ·5H 2 O have a 3D structure constructed from two crystallographically unique MO 5 (H 2 O) 3 square-antiprismatic (CN = 8) metal centers. In these structures, the squarate ligands bind to the metal centers with varying coordination modes and denticities. The results of this study provide another example of the nonparallel chemistry between the lanthanides and transplutonium elements. From the crystallographic data for the isotypic series M 2 (C 4 O 4 ) 3 (H 2 O) 4 (M = La–Nd, Sm, Eu) and the linear regression fit to a plot of the unit cell volume as a function of the cube of the ionic radius, the nine-coordinate ionic radius of Cf 3+ was determined to be 1.127 ± 0.003 Å. Lastly, computational analysis of the americium and californium complexes M 2 (C 4 O 4 ) 3 (H 2 O) 4 and M 2 (C 4 O 4 ) 2 (C 2 O 4 )(H 2 O) 4 reveals three important attributes: (i) the 5f orbitals are nonbonding in all cases, with the bonding differences occurring with the empty 6d orbitals; (ii) the Cf complexes exhibit more covalent character than their Am counterparts; and (iii) there is more covalent character in the squarate-oxalate complexes than in the squarate complexes.

Crystallography↗

DOE OSTI2022

Structural and Bonding Analysis in Monomeric Actinide(IV) Oxalate from Th(IV) to Pu(IV): Comparison with the An(IV) Nitrate Series

In this work, single-crystal X-ray diffraction (SC-XRD) structures and Raman spectra of a series of new isomorphous molecular An(IV)-oxalate compounds (Th, U, Np, and Pu) are reported. These complexes are crystallized with cobalt(III) hexamine ([Co(NH 3 ) 6 ] 3+ ) as the counter cations, [Co(NH 3 ) 6 ] 2 [An(C 2 O 4 ) 5 ]·4H 2 O, revealing five bidentate nonbridging oxalate ligands in the first coordination sphere (CN = 10). The nonbridging oxalate is rather uncommon for An(IV)-oxalate systems, which are widely characterized as polymeric compounds. Density functional theory (DFT) calculations were performed to examine the bonding between An(IV) cations and oxalate ligands. For comparison, we also report results obtained for the An(IV)-hexanitrate series, [(C 2 H 5 ) 4 N] 2 [An(NO 3 ) 6 ] (with An = Th, U, Np, Pu, and Ce), which consists of O-donor ligands as well but with a larger coordination number (CN = 12). The bonding analysis confirms that the actinide–oxygen bond is predominantly ionic with a minor increase in covalency from Th to U and slight variations from U to Pu. Further comparison showed that the charge transfer increases slightly when increasing the number of anions in the coordination sphere (C 2 O$_4^{2–}$: CN = 10; NO$_3^–$: CN = 12), but covalent effects as indicated by the amount of internuclear electron density accumulation are small and similar for oxalate and nitrate.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

Effects of Methylating Imidazolium-Based Ionic Liquids on Viscosity: New Insights from the Compensated Arrhenius Formalism

Methylation of the C(2) carbon on imidazolium-based room temperature ionic liquids (RTILs) causes an unexpected increase in viscosity when paired with the anion bis(trifluoromethylsulfonamide) [Tf 2 N] – , but the viscosity decreases when the methylated imidazolium is paired with a tetracyanoborate [B(CN) 4 ] – anion. Herein, this paper investigates these different observations in viscosity using the compensated Arrheniusformalism (CAF) for fluidity (inverse viscosity), which assumes fluidity to be a thermally activated process. CAF activation energies are determined for imidazolium [Tf 2 N] – and methylated imidazolium [Tf 2 N] – and compared to imidazolium [B(CN) 4 ] – and methylated imidazolium [B(CN) 4 ] – . The results show that the activation energy increases with methylation for [Tf 2 N] – , but it decreases with methylation for [B(CN) 4 ] – . The CAF results also yield information concerning the entropy of activation, which are compared for the two systems

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2024

Catalytic Reduction of Cyanide to Ammonia and Methane at a Mononuclear Fe Site

Nitrogenase enzymes catalyze nitrogen reduction (N 2 R) to ammonia and also the reduction of non-native substrates, including the 7H + /6e – reduction of cyanide to CH 4 and NH 3 . CN – and N 2 are isoelectronic, and it is hence fascinating to compare the mechanisms of synthetic Fe catalysts capable of both CN – and N 2 reduction. Here, we describe the catalytic reduction of CN – to NH 3 and CH 4 by a highly selective (P 3 Si )Fe(CN) catalyst (P 3 Si represents a tris(phosphine)silyl ligand). Catalysis is driven in the presence of excess acid ([Ph 2 NH 2 ]OTf) and reductant ((C 6 H 6 ) 2 Cr), with turnover as high as 73 demonstrated.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2024

Long Excited-State Lifetimes in Three-Coordinate Copper(I) Complexes via Triplet–Triplet Energy Transfer to Pyrene-Decorated Isocyanides

There has been much effort to improve excited-state lifetimes in photosensitizers based on earth-abundant first-row transition metals. Copper(I) complexes have gained significant attention in this field, and in most cases, sterically driven approaches are used to optimize their lifetimes. This study presents a series of three-coordinate copper(I) complexes (Cu1–Cu3) where the excited-state lifetime is extended by triplet–triplet energy transfer. The heteroleptic compounds feature a cyclohexyl-substituted β-diketiminate (CyNacNac Me ) paired with aryl isocyanide ligands, giving the general formula Cu(CyNacNac Me )(CN-Ar) (CN-dmp = 2,6-dimethylphenyl isocyanide for Cu1; CN-pyr = 1-pyrenyl isocyanide for Cu2; CN-dmp-pyr = 2,6-dimethyl-4-(1-pyrenyl)phenyl isocyanide for Cu3). The nature, energies, and dynamics of the low-energy triplet excited states are assessed with a combination of photoluminescence measurements at room temperature and 77 K, ultrafast transient absorption (UFTA) spectroscopy, and DFT calculations. The complexes with the pyrene-decorated isocyanides (Cu2 and Cu3) exhibit extended excited-state lifetimes resulting from triplet–triplet energy transfer (TTET) between the short-lived charge-transfer excited state ( 3 CT) and the long-lived pyrene-centered triplet state ( 3 pyr). This TTET process is irreversible in Cu3, producing exclusively the 3 pyr state, and in Cu2, the 3 CT and 3 pyr states are nearly isoenergetic, enabling reversible TTET and long-lived 3 CT luminescence. The improved photophysical properties in Cu2 and Cu3 result in improvements in activity for both photocatalytic stilbene E/Z isomerization via triplet energy transfer and photoredox transformations involving hydrodebromination and C–O bond activation. Furthermore, these results illustrate that the extended excited-state lifetimes achieved through TTET result in newly conceived photosynthetically relevant earth-abundant transition metal complexes.

14 SOLAR ENERGY↗

DOE OSTI2022

Maritime Aerosol and CCN Profiles Derived From Ship₋Based Measurements Over Eastern North Pacific During MAGIC

Atmospheric aerosols are widely recognized to give rise to a substantial radiative forcing to the climate by scattering and absorbing radiation and by modifying the microphysical, lifetime, and radiative properties of clouds. During the Marine ARM GPCI Investigation of Clouds (MAGIC) over the Eastern North Pacific (ENP), the ship-based measured cloud condensation nuclei (CCN) concentration at 0.2% supersaturation (N CCN,0.2 ) and condensation nuclei concentration (N CN ) had mean values of 116.7 and 219.4 cm ⁻3 , with the highest concentrations found closest to LA due to an increase in aerosol sources. Moving westward, both N CCN,0.2 and N CN gradually decreased until stabilizing near 100 cm ⁻3 and 200 cm ⁻3 , respectively. Using the methods proposed by Ghan and Collins (2004), https://doi.org/10.1175/1520-0426(2004)021<0387:uoisdt>2.0.co;2 and Ghan et al. (2006), https://doi.org/10.1029/2004jd005752, N CCN,0.2 profiles are retrieved using the surface measured N CCN,0.2 as a constraint. For coupled conditions, correlations between the retrieved N CCN,0.2 profiles and cloud-droplet number concentration (N C ) increase from 0.26 at the surface to 0.38 near cloud base, particularly true for non-drizzling clouds. Although the correlations are lower than expected, the percentage increase (46.2%) is encouraging. Finally, the relationships between cloud breakup (CB) and the stratocumulus to cumulus transition (SCT) with environmental conditions and associated aerosols are also studied. The decreased N CN trend east of CB is mainly caused by precipitation scavenging, while the increased N CN trend west of CB is strongly associated with the increased surface wind speed and fewer drizzle events. A further study is needed using high-resolution models to simulate these events.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2020

Enhanced stability of silicon for photoelectrochemical water oxidation through self-healing enabled by an alkaline protective electrolyte

Alkaline electrolytes impede the corrosion of Si photoanodes under positive potentials and/or illumination, due to the formation of a SiO x layer that etches 2–3 orders of magnitude more slowly than Si. Hence during water oxidation under illumination, pinholes in protection layers on Si photoanodes result in the local formation of a protective, stabilizing passive oxide on the Si surface. However, operation under natural diurnal insolation cycles additionally requires protection strategies that minimize the dark corrosive etching rate of Si at pinholes. We show herein that addition of [Fe(CN) 6 ] 3- to 1.0 M KOH(aq) results in a self-healing process that extends the lifetime to >280 h of an np + -Si(100) photoanode patterned with an array of Ni catalyst islands operated under simulated day/night cycles. The self-healing [Fe(CN) 6 ] 3- additive caused the exposed Si(100) surface to etch >180 times slower than the Si etch rate in 1.0 M KOH(aq) alone. No appreciable difference in etch rate or facet preference was observed between Si(100) and Si(111) surfaces in 1.0 M KOH(aq) with [Fe(CN) 6 ] 3- , indicating that the surface conformally oxidized before Si dissolved. The presence of [Fe(CN) 6 ] 3- minimally impacted the faradaic efficiency or overpotential of p + -Si/Ni electrodes for the oxygen-evolution reaction.

25 ENERGY STORAGE↗

DOE OSTI2020

Universal temperature dependence of the London penetration depth in κ - ( ET ) 2 X superconductors

High-precision radio-frequency magnetic susceptibility measurements were performed on single crystals of fully deuterated $κ-(ET)_2Cu[N(CN)_2]\,Br$, hereafter designated as $κ-(ET)_2Cu[N(CN)_2]\,Br$. This material phase separates into superconducting and antiferromagnetic regions, the degree of which depends strongly upon the cooling rate. Here, we show that the screening fraction $η_{sc}$ varies logarithmically with the cooling rate over nearly five decades. The average size of superconducting regions is estimated to vary from 5 to $40μm$, depending upon cooling rate, consistent with previous infrared microscopy measurements. In the region $T≲T_c/3$, the effective magnetic penetration depth exhibits power-law behavior $λ(T)-λ(0)~T^n$ with $n=1.6$, independent of the cooling rate. Changes in cooling rate and the consequent phase separation evidently do not introduce the kind of disorder that would alter the exponent $n$ in a $d$-wave superconductor. The exponent remains close to $n=$ 1.5, reported in single crystals of $κ-(ET)_2Cu[N(CN)_2]\,Br$ and $κ-(ET)_2Cu(NCS)_2$ [A. Carrington et al., Phys. Rev. Lett 83, 4172 (1999)]. The transition temperature fell linearly with $1-η_{sc}$. Measurements were also made on $κ-(ET)_2Cu[N(CN)_2]\,Cl$ of normal isotopic abundance in which a very small amount of superconducting phase $η_{sc}≈10^{-4}$ developed, presumably through the strain-induced sample mounting. This material showed a power-law exponent of $n=1.64$, independent of the cooling rate.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2020

Materials Data on ZnAs2C12(NF)12 by Materials Project

Zn(CN)6(CN)6(AsF6)2 crystallizes in the trigonal R-3 space group. The structure is zero-dimensional and consists of eighteen hydrogen cyanide molecules, six AsF6 clusters, and three Zn(CN)6 clusters. In each AsF6 cluster, As is bonded in an octahedral geometry to six F1- atoms. There is three shorter (1.77 Å) and three longer (1.78 Å) As–F bond length. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one As atom. In the second F1- site, F1- is bonded in a single-bond geometry to one As atom. In each Zn(CN)6 cluster, Zn2+ is bonded in an octahedral geometry to six equivalent N3- atoms. All Zn–N bond lengths are 2.15 Å. C+3.83+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.16 Å. N3- is bonded in a linear geometry to one Zn2+ and one C+3.83+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on AlZnB5H20C5(NO2)5 by Materials Project

Al(BO2)5ZnH20(CN)5 crystallizes in the triclinic P1 space group. The structure is three-dimensional and consists of two ZnH20(CN)5 clusters and one Al(BO2)5 framework. In one of the ZnH20(CN)5 clusters, Zn2+ is bonded in a trigonal bipyramidal geometry to five N3- atoms. There are a spread of Zn–N bond distances ranging from 2.09–2.20 Å. There are five inequivalent C1- sites. In the first C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.47 Å. Both C–H bond lengths are 1.10 Å. In the second C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. In the third C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. In the fourth C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. In the fifth C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. There are five inequivalent N3- sites. In the first N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. Both N–H bond lengths are 1.03 Å. In the second N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. There is one shorter (1.03 Å) and one longer (1.04 Å) N–H bond length. In the third N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. There is one shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. In the fourth N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. Both N–H bond lengths are 1.02 Å. In the fifth N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. Both N–H bond lengths are 1.03 Å. There are twenty inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the sixteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the seventeenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the eighteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the nineteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the twentieth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In one of the ZnH20(CN)5 clusters, Zn2+ is bonded in a trigonal bipyramidal geometry to five N3- atoms. There are a spread of Zn–N bond distances ranging from 2.07–2.22 Å. There are five inequivalent C1- sites. In the first C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. In the second C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. In the third C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. In the fourth C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. In the fifth C1- site, C1- is bonded in a distorted trigonal non-coplanar geometry to one N3- and two H1+ atoms. The C–N bond length is 1.48 Å. Both C–H bond lengths are 1.10 Å. There are five inequivalent N3- sites. In the first N3- site, N3- is bonded in a 4-coordinate geometry to one Zn2+, one C1-, and two H1+ atoms. There is one shorter (1.03 Å) and one longer (1.04 Å) N–H bond length. In the second N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. There is one shorter (1.03 Å) and one longer (1.04 Å) N–H bond length. In the third N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. Both N–H bond lengths are 1.02 Å. In the fourth N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. There is one shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. In the fifth N3- site, N3- is bonded to one Zn2+, one C1-, and two H1+ atoms to form distorted corner-sharing NZnH2C tetrahedra. There is one shorter (1.02 Å) and one longer (1.03 Å) N–H bond length. There are twenty inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the second H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the third H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the fifth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the sixth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the seventh H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one C1- atom. In the eleventh H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the twelfth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the thirteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fourteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the fifteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the sixteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the seventeenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the eighteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the nineteenth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the twentieth H1+ site, H1+ is bonded in a single-bond geometry to one N3- atom. In the Al(BO2)5 framework, there are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Al–O bond distances ranging from 1.74–1.76 Å. In the second Al3+ site, Al3+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Al–O bond distances ranging from 1.74–1.76 Å. There are ten inequivalent B3+ sites. In the first B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.41 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.40 Å. In the third B3+ site, B3+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.48 Å) and two longer (1.49 Å) B–O bond length. In the fourth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.42 Å. In the fifth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.34–1.42 Å. In the sixth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.34–1.41 Å. In the seventh B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.41 Å. In the eighth B3+ site, B3+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of B–O bond distances ranging from 1.47–1.50 Å. In the ninth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.35–1.41 Å. In the tenth B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.36–1.41 Å. There are twenty inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Al3+ and one B3+ atom. In the second O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the third O2- site, O2- is bonded in a linear geometry to one Al3+ and one B3+ atom. In the fourth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the fifth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the eighth O2- site, O2- is bonded in a linear geometry to one Al3+ and one B3+ atom. In the ninth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the tenth O2- site, O2- is bonded in a linear geometry to one Al3+ and one B3+ atom. In the eleventh O2- site, O2- is bonded in a linear geometry to one Al3+ and one B3+ atom. In the twelfth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one B3+ atom. In the fourteenth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the fifteenth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the sixteenth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the seventeenth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the eighteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one B3+ atom. In the nineteenth O2- site, O2- is bonded in a bent 120 degrees geometry to two B3+ atoms. In the twentieth O2- site, O2- is bonded in a linear geometry to one Al3+ and one B3+ atom.

36 MATERIALS SCIENCE↗

DOE OSTI2024

Hydrodynamic Simulations of Oxygen–Neon Classical Novae as Galactic 7 Li Producers and Potential Accretion-induced Collapse Progenitors*

Abstract We report on studies of classical nova (CN) explosions where we follow the evolution of thermonuclear runaways (TNRs) on oxygen–neon (ONe) white dwarfs (WDs). Using NOVA, a 1D hydrodynamic computer code, we accrete solar matter until the TNR is ongoing and then switch to a mixed composition. This approach is guided by the results of multidimensional studies of TNRs in WDs, which find that sufficient mixing with WD core material occurs after the TNR is well underway, and levels of enrichment of the CNONeMg elements are reached that agree with observations of CN ejecta abundances. Because the amount of accreted material is inversely proportional to the oxygen abundance, by first accreting solar matter, the amount of accreted material is larger than in those simulations with an initially enriched composition. We vary the mass of the WD (from 0.6 M ⊙ to 1.35 M ⊙ ) and the composition of the mixed materials. Our results show large enrichments of 7 Be in the ejected gases, implying that ONe CNe and CO CNe may be responsible for a significant fraction (∼100 M ⊙ ) of the Galactic 7 Li (∼1000 M ⊙ ). The production of 22 Na and 26 Al in CN explosions and the γ -ray emission predicted by our simulations are discussed. The WDs in all our simulations eject less material than they accrete and we predict that the WD is growing in mass as a consequence of the CN outburst. ONe CNe, therefore, may be an important channel for accretion-induced collapse events.

Starrfield, Sumner (ORCID:0000000213596312)↗