Coarse-grained modeling of the nucleation of polycyclic aromatic hydrocarbons into soot precursors

2019 ◽  
Vol 21 (9) ◽  
pp. 5123-5132 ◽  
Author(s):  
J. Hernández-Rojas ◽  
F. Calvo
Keyword(s):  
Monte Carlo ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Physical Growth ◽  
Coarse Grained ◽  
Soot Precursors ◽  
Polycyclic Aromatic ◽  
Hydrocarbon Molecules ◽  
A Minor ◽  
Monte Carlo Framework

The aggregation and physical growth of polycyclic aromatic hydrocarbon molecules was simulated using a coarse-grained potential and a stochastic Monte Carlo framework. In agreement with earlier studies, homomolecular nucleation of pyrene, coronene and circumcoronene is found to be limited at temperatures in the 500–1000 K range. Heteromolecular nucleation is found to occur with a minor spontaneous segregation toward pure and equi concentrations.

Dynamics and thermodynamics of the coronene octamer described by coarse-grained potentials

2017 ◽  
Vol 19 (3) ◽  
pp. 1884-1895 ◽  
Author(s):  
J. Hernández-Rojas ◽  
F. Calvo ◽  
S. Niblett ◽  
D. J. Wales
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Finite Temperature ◽  
Coarse Grained ◽  
Energy Landscapes ◽  
Equilibrium Dynamics ◽  
Polycyclic Aromatic

Coarse-grained models developed for polycyclic aromatic hydrocarbons based on the Paramonov–Yaliraki potential have been employed to investigate the finite temperature thermodynamics, out-of-equilibrium dynamics, energy landscapes, and rearrangement pathways of the coronene octamer.

scholarly journals Omega and Cluj-Ilmenau Indices of Hydrocarbon Molecules “Polycyclic Aromatic Hydrocarbons PAHk”

2016 ◽  
Vol 04 (04) ◽  
pp. 91-96 ◽  
Author(s):  
M. R. Rajesh Kanna ◽  
R. Pradeep Kumar ◽  
Muhammad Kamran Jamil ◽  
Mohammad Reza Farahani
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Polycyclic Aromatic ◽  
Hydrocarbon Molecules

scholarly journals Products from the Incomplete Metabolism of Pyrene by Polycyclic Aromatic Hydrocarbon-Degrading Bacteria

2000 ◽  
Vol 66 (5) ◽  
pp. 1917-1922 ◽  
Author(s):  
Chikoma Kazunga ◽  
Michael D. Aitken
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Pseudomonas Stutzeri ◽  
Minor Effect ◽  
Bacterial Strains ◽  
Phenanthrene Degradation ◽  
Degrading Bacteria ◽  
Subsequent Degradation ◽  
Polycyclic Aromatic ◽  
A Minor

ABSTRACT Pyrene is a regulated pollutant at sites contaminated with polycyclic aromatic hydrocarbons (PAH). It is mineralized by some bacteria but is also transformed to nonmineral products by a variety of other PAH-degrading bacteria. We examined the formation of such products by four bacterial strains and identified and further characterized the most apparently significant of these metabolites.Pseudomonas stutzeri strain P16 and Bacillus cereus strain P21 transformed pyrene primarily tocis-4,5-dihydro-4,5-dihydroxypyrene (PYRdHD), the first intermediate in the known pathway for aerobic bacterial mineralization of pyrene. Sphingomonas yanoikuyae strain R1 transformed pyrene to PYRdHD and pyrene-4,5-dione (PYRQ). Both strain R1 and Pseudomonas saccharophila strain P15 transform PYRdHD to PYRQ nearly stoichiometrically, suggesting that PYRQ is formed by oxidation of PYRdHD to 4,5-dihydroxypyrene and subsequent autoxidation of this metabolite. A pyrene-mineralizing organism,Mycobacterium strain PYR-1, also transforms PYRdHD to PYRQ at high initial concentrations of PYRdHD. However, strain PYR-1 is able to use both PYRdHD and PYRQ as growth substrates. PYRdHD strongly inhibited phenanthrene degradation by strains P15 and R1 but had only a minor effect on strains P16 and P21. At their aqueous saturation concentrations, both PYRdHD and PYRQ severely inhibited benzo[a]pyrene mineralization by strains P15 and R1. Collectively, these findings suggest that products derived from pyrene transformation have the potential to accumulate in PAH-contaminated systems and that such products can significantly influence the removal of other PAH. However, these products may be susceptible to subsequent degradation by organisms able to metabolize pyrene more extensively if such organisms are present in the system.

scholarly journals Influences of the molecular fuel structure on combustion reactions towards soot precursors in selected alkane and alkene flames

2018 ◽  
Vol 20 (16) ◽  
pp. 10780-10795 ◽  
Author(s):  
Lena Ruwe ◽  
Kai Moshammer ◽  
Nils Hansen ◽  
Katharina Kohse-Höinghaus
Keyword(s):  
Mass Spectrometry ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Molecular Beam ◽  
Molecular Beam Mass Spectrometry ◽  
Formation Kinetics ◽  
Soot Precursors ◽  
Polycyclic Aromatic ◽  
Kinetics Of

Flame-sampling molecular beam mass spectrometry enables valuable insights into the fuel-structure-dependent formation kinetics of polycyclic aromatic hydrocarbons and their precursors.

scholarly journals Assessment of Density Functional Theory in Predicting Interaction Energies Between Water and Polycyclic Aromatic Hydrocarbons: From Water on Benzene to Water on Graphene

2018 ◽  
Author(s):  
Adeayo Ajala ◽  
Vamsee K. Voora ◽  
Narbe Mardirossian ◽  
Filipp Furche ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Interaction Energies ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Polycyclic Aromatic ◽  
Hydrocarbon Molecules

<div> <div> <div> <p>The interaction of water with polycyclic aromatic hydrocarbons, from benzene to graphene, is investigated using various exchange-correlation functionals selected across generalized gradient approximation (GGA), meta-GGA, and hybrid families within the density functional theory (DFT) hierarchy. The accuracy of the different functionals is assessed through comparisons with high-level electronic structure methods, including random phase approximation (RPA), diffusion Monte Carlo (DMC), and coupled-cluster with single, double, and perturbative triple excitations (CCSD(T)). Relatively large variations are found in the interaction energies predicted by different DFT models, with GGA functionals underestimating the interaction strength for configurations with the water oxygen pointing toward the aromatic molecules, and the meta-GGA B97M-rV and hybrid ωB97M-V functionals providing nearly quantitative agreement with CCSD(T) values available for the water-benzene, water-coronene, and water-circumcoronene dimers, which, in turn, are within ∼1 kcal/mol of the corresponding RPA and DMC results. Similar trends among GGA, meta-GGA, and hybrid functionals are observed for the larger polycyclic aromatic hydrocarbon molecules considered in this analysis (up to C216H36). By performing absolutely localized molecular orbital energy decomposition analyses (ALMO-EDA) of the DFT results, it is found that, independently of the number of carbon atoms and exchange-correlation functional, the dominant contributions to the interaction energies between water and polycyclic aromatic hydrocarbon molecules are the electrostatic and dispersion terms while polarization and charge transfer effects are negligibly small. Calculations carried out with GGA and meta-GGA functionals indicate that, as the number of carbon atoms increases, the interaction energies slowly converge to the corresponding values obtained for an infinite graphene sheet. Importantly, water-graphene interaction energies calculated with the B97M-rV functional appear to deviate by more than 1 kcal/mol from the available RPA and DMC values. </p> </div> </div> </div>

scholarly journals Assessment of Density Functional Theory in Predicting Interaction Energies Between Water and Polycyclic Aromatic Hydrocarbons: From Water on Benzene to Water on Graphene

2018 ◽  
Author(s):  
Adeayo Ajala ◽  
Vamsee K. Voora ◽  
Narbe Mardirossian ◽  
Filipp Furche ◽  
Francesco Paesani
Keyword(s):  
Density Functional Theory ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbons ◽  
Density Functional ◽  
Interaction Energies ◽  
Functional Theory ◽  
Exchange Correlation ◽  
Polycyclic Aromatic ◽  
Hydrocarbon Molecules

<div> <div> <div> <p>The interaction of water with polycyclic aromatic hydrocarbons, from benzene to graphene, is investigated using various exchange-correlation functionals selected across generalized gradient approximation (GGA), meta-GGA, and hybrid families within the density functional theory (DFT) hierarchy. The accuracy of the different functionals is assessed through comparisons with high-level electronic structure methods, including random phase approximation (RPA), diffusion Monte Carlo (DMC), and coupled-cluster with single, double, and perturbative triple excitations (CCSD(T)). Relatively large variations are found in the interaction energies predicted by different DFT models, with GGA functionals underestimating the interaction strength for configurations with the water oxygen pointing toward the aromatic molecules, and the meta-GGA B97M-rV and hybrid ωB97M-V functionals providing nearly quantitative agreement with CCSD(T) values available for the water-benzene, water-coronene, and water-circumcoronene dimers, which, in turn, are within ∼1 kcal/mol of the corresponding RPA and DMC results. Similar trends among GGA, meta-GGA, and hybrid functionals are observed for the larger polycyclic aromatic hydrocarbon molecules considered in this analysis (up to C216H36). By performing absolutely localized molecular orbital energy decomposition analyses (ALMO-EDA) of the DFT results, it is found that, independently of the number of carbon atoms and exchange-correlation functional, the dominant contributions to the interaction energies between water and polycyclic aromatic hydrocarbon molecules are the electrostatic and dispersion terms while polarization and charge transfer effects are negligibly small. Calculations carried out with GGA and meta-GGA functionals indicate that, as the number of carbon atoms increases, the interaction energies slowly converge to the corresponding values obtained for an infinite graphene sheet. Importantly, water-graphene interaction energies calculated with the B97M-rV functional appear to deviate by more than 1 kcal/mol from the available RPA and DMC values. </p> </div> </div> </div>

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