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

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.

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>

The Assessment of Contamination and Source of Polycyclic Aromatic Hydrocarbons from the Sediments of the Someş River

2019 ◽  
Vol 64 (1) ◽  
pp. 55-67
Author(s):  
Vlad Pӑnescu ◽  
◽  
Mihaela Cӑtӑlina Herghelegiu ◽  
Sorin Pop ◽  
Mircea Anton ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Polycyclic Aromatic

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

1,1’-Biaceanthrylene and 2,2'-Biaceanthrylene: Models for Linking Larger Polycyclic Aromatic Hydrocarbons via Five-Membered Rings

2019 ◽  
Author(s):  
Yachu Du ◽  
Kyle Plunkett
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic Hydrocarbon ◽  
Aromatic Hydrocarbon ◽  
Electronic Properties ◽  
Aromatic Hydrocarbons ◽  
Model Systems ◽  
Redox Potentials ◽  
Dimer Model ◽  
Optical And Electronic Properties ◽  
Polycyclic Aromatic

We show that polycyclic aromatic hydrocarbon (PAH) chromophores that are linked between two five-membered rings can access planarized structures with reduced optical gaps and redox potentials. Two aceanthrylene chromophores were connected into dimer model systems with the chromophores either projected outward (2,2’-biaceanthrylene) or inward (1,1’-biaceanthrylene) and the optical and electronic properties were compared. Only the planar 2,2’-biaceanthrylene system showed significant reductions of the optical gaps (1 eV) and redox potentials in relation to the aceanthrylene monomer.<br>

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