Ab initio simulations of liquid carbon monoxide at high pressure

Leonhardi, T. C.; Militzer, Burkhard

doi:10.1016/j.hedp.2017.02.005

Cited by 11 publications

(8 citation statements)

References 31 publications

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“…Structurally, the aggregate formed in the 500 atom system is of low density while in the 1000 atom system, a droplet resembling liquid carbon is formed. Our findings are consistent with previous work 19 , which mapped a hypothetical CO phase diagram at extreme conditions via DFT-MD on a 108 atom system. At conditions above ≈ 15 GPa and 2000 K, the authors identified the presence of a "polymeric carbon" phase, i.e.…”

Section: Carbon Clustering and Finite Size Effectssupporting

confidence: 92%

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Development of the ChIMES Force Field for Reactive Molecular Systems: Carbon Monoxide at Extreme Conditions

Lindsey¹,

Goldman²,

Fried³

et al. 2019

Preprint

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<p>We have developed a transferable reactive force field for C/O systems under extreme temperature and pressure conditions based on the many-body Chebyshev Interaction Model for Efficient Simulation (ChIMES). The resulting model is shown to recover much of the accuracy of DFT for prediction of structure, dynamics and chemistry when applied to dissociative systems at 1:1 and 1:2 C:O ratios, as well as molten carbon. Our C/O modeling approach exhibits a 10<sup>4</sup> increase in efficiency and linear system size scalability over standard quantum molecular dynamics methods, allowing simulation of significantly larger systems than previously possible. Furthermore, we show that system sizes of at least 500 atoms are required to observe the formation of experimentally predicted molten carbon condensates under oxygen-deficient conditions, indicative of possible system size effects in quantum simulations of these types of systems. Overall, we find the present ChIMES model to be well suited for modeling chemical processes and cluster formation at pressures and temperatures typical of shock waves. We expect that the present C/O modeling paradigm can serve as a template for the development of a high pressure --high temperature organic chemistry force-field. </p>

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Section: Carbon Clustering and Finite Size Effectssupporting

confidence: 92%

“…However, both the target time and length scales of the carbon condensation problem are well outside each method's range of applicability. For example, a recent attempt to generate a first-principles-derived phase diagram for CO at extreme conditions was confined to 108 atoms, and 2-12 ps simulations 19 .…”

Section: Introductionmentioning

confidence: 99%

Development of the ChIMES Force Field for Reactive Molecular Systems: Carbon Monoxide at Extreme Conditions

Lindsey¹,

Goldman²,

Fried³

et al. 2019

Preprint

View full text Add to dashboard Cite

show abstract

“…4, C 2n O n clusters of roughly 250 atoms begin to form as early as 3 ps. Consistent with previous DFT studies 38 , these early clusters appear to be covalently bonded, with an extended, low density shape and oxygen distributed homogeneously throughout. They continue to grow and merge to form larger seeds, eventually densifying into small liquid carbon nanodroplets by expelling interior oxygen.…”

Section: 2supporting

confidence: 88%

Ultrafast shock synthesis of nanocarbon from a liquid precursor

et al. 2020

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Carbon nanoallotropes are important nanomaterials with unusual properties and promising applications. High pressure synthesis has the potential to open new avenues for controlling and designing their physical and chemical characteristics for a broad range of uses but it remains little understood due to persistent conceptual and experimental challenges, in addition to fundamental physics and chemistry questions that are still unresolved after many decades. Here we demonstrate sub-nanosecond nanocarbon synthesis through the application of laser-induced shock-waves to a prototypical organic carbon-rich liquid precursorliquid carbon monoxide. Overlapping large-scale molecular dynamics simulations capture the atomistic details of the nanoparticles' formation and evolution in a reactive environment and identify classical evaporation-condensation as the mechanism governing their growth on these time scales.

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“…With density functional molecular dynamics simulations, Boates et al [39] predicted CO 2 to exhibit a liquid-liquid phase transition at 0.5 Mbar. Leonhardi and Militzer [40] predicted a similar phase transition for CO to occur between 0.1 and 0.2 Mbar. In the simulations, CO was also observed to change phase from a molecular to a polymeric fluid.…”

Section: Symmetry and Structure Predictionmentioning

confidence: 78%

Prediction of novel high-pressure H2O -NaCl and carbon oxide compounds with a symmetry-driven structure search algorithm

2018

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Crystal structure prediction with theoretical methods is particularly challenging when unit cells with many atoms need to be considered. Here we employ a symmetry-driven structure search (SYDSS) method and combine it with density functional theory (DFT) to predict novel crystal structures at high pressure. We sample randomly from all 1,506 Wyckoff positions of the 230 space groups to generate a set of initial structures. During the subsequent structural relaxation with DFT, existing symmetries are preserved, but the symmetries and the space group may change as atoms move to more symmetric positions. By construction, our algorithm generates symmetric structures with high probability without excluding any configurations. This improves the search efficiency, especially for large cells with 20 atoms or more. We apply our SYDSS algorithm to identify stoichiometric (H2O)n-(NaCl)m and CnOm compounds at high pressure. We predict a novel H2O-NaCl structure with Pnma symmetry to form at 3.4 Mbar, which is within the range of diamond anvil experiments. In addition, we predict a novel C2O structure at 19.8 Mbar and C4O structure at 44.0 Mbar with Pbca and C2/m symmetry respectively.PACS numbers:

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Ab initio simulations of liquid carbon monoxide at high pressure

Cited by 11 publications

References 31 publications

Development of the ChIMES Force Field for Reactive Molecular Systems: Carbon Monoxide at Extreme Conditions

Development of the ChIMES Force Field for Reactive Molecular Systems: Carbon Monoxide at Extreme Conditions

Ultrafast shock synthesis of nanocarbon from a liquid precursor

Prediction of novel high-pressure H2O -NaCl and carbon oxide compounds with a symmetry-driven structure search algorithm

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