The physisorption of molecular hydrogen onto coronene is studied using a multi-scale theoretical approach with Density Func- tional Theory (DFT) calculations and Molecular Dynamics (MD) simulations. We consider two different kinds of model confor- mations for the approach of hydrogen towards the coronene i.e., systematic and random. For the systematic attack of hydrogen over coronene, the resulting potential energy profiles from DFT analysis are further found resembling to the Morse potential, and even to the largely flexible Murrell-Sorbie (M-S) potential. The resulting M-S fitting also shows a zero-point energy correction of ∼ 16-17 %. On the other hand, the potential energies from the random approach has been implemented into the Improved Lennard-Jones (ILJ) force field of DL−POLY package following a prior statistical treatment. The MD simulations have been performed at different temperatures from 10 to 390 K. For the interaction of seven hydrogen molecules with coronene, the DFT method shows an average interaction energy of −3.85 kJ/mol per H2, which is standing slightly below the Coupled Cluster value (CCSD(T)) of −4.71 kJ/mol that was calculated for a single molecule in the most favorable situation. Moreover, the MD calcu- lations reveal a mean interaction energy of −3.69 kJ/mol per H2 (a gross mean Ec f g of −25.98 kJ/mol at T = 299.97 K), which is again in good agreement to the aforementioned DFT results, proving the quality of the used approach for the study of van der Waals interactions between hydrogen and graphene.

Multi-scale theoretical investigation of molecular hydrogen adsorption over graphene: coronene as a case study

FAGINAS LAGO, Maria Noelia;
2014

Abstract

The physisorption of molecular hydrogen onto coronene is studied using a multi-scale theoretical approach with Density Func- tional Theory (DFT) calculations and Molecular Dynamics (MD) simulations. We consider two different kinds of model confor- mations for the approach of hydrogen towards the coronene i.e., systematic and random. For the systematic attack of hydrogen over coronene, the resulting potential energy profiles from DFT analysis are further found resembling to the Morse potential, and even to the largely flexible Murrell-Sorbie (M-S) potential. The resulting M-S fitting also shows a zero-point energy correction of ∼ 16-17 %. On the other hand, the potential energies from the random approach has been implemented into the Improved Lennard-Jones (ILJ) force field of DL−POLY package following a prior statistical treatment. The MD simulations have been performed at different temperatures from 10 to 390 K. For the interaction of seven hydrogen molecules with coronene, the DFT method shows an average interaction energy of −3.85 kJ/mol per H2, which is standing slightly below the Coupled Cluster value (CCSD(T)) of −4.71 kJ/mol that was calculated for a single molecule in the most favorable situation. Moreover, the MD calcu- lations reveal a mean interaction energy of −3.69 kJ/mol per H2 (a gross mean Ec f g of −25.98 kJ/mol at T = 299.97 K), which is again in good agreement to the aforementioned DFT results, proving the quality of the used approach for the study of van der Waals interactions between hydrogen and graphene.
2014
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11391/1290898
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