Pellenq Roland J-M, Marinelli Francis, Fuhr Javier D, Fernandez-Alonso Felix, Refson Keith
Centre Interdisciplinaire des Nanosciences de Marseille, UPR-CNRS 3118, Campus de Luminy, 13288 Marseille Cedex 09, France.
J Chem Phys. 2008 Dec 14;129(22):224701. doi: 10.1063/1.3037211.
Molecular hydrogen adsorption between two Li, K-doped coronene molecules (taken as local environment of carbon microporous materials) is studied by first-principles DFT-B3LYP calculations. These cluster calculations are complemented with periodic DFT-LDA/GGA calculations on extended Li- and K-doped structures. In all cases, energy minimization calculations unravel that there is a stable adsorption site for molecular hydrogen in these Li- and K-doped sp(2) carbon structures with large adsorption energies. This is the direct consequence of the significant charge transfer from the doping agents on neighboring slab carbon atoms, which allows the coupling of the molecular H(2) polarizability with the resulting substrate electric field (polarization interaction) that in turn induces the stabilization of molecular hydrogen. These calculations also give an insight on the atomic configurations of interlayer species (H(2) and LiK) as the interlayer spacing increases. It can be shown that large positional changes correlate with electronic properties of interlayer species. The confined hydrogen molecule does not show any tendency for dissociation and adopts a position in the interlayer void that is deeply related to that of doping ions.
通过第一性原理DFT - B3LYP计算研究了两个锂、钾掺杂的并五苯分子（作为碳微孔材料的局部环境）之间的分子氢吸附。这些团簇计算通过对扩展的锂和钾掺杂结构进行周期性DFT - LDA/GGA计算得到补充。在所有情况下，能量最小化计算表明，在这些具有大吸附能的锂和钾掺杂的sp(2)碳结构中存在分子氢的稳定吸附位点。这是由于掺杂剂向相邻板状碳原子显著电荷转移的直接结果，这使得分子H(2)的极化率与产生的衬底电场（极化相互作用）耦合，进而导致分子氢的稳定。这些计算还揭示了随着层间距增加层间物种（H(2)和LiK）的原子构型。可以表明，大的位置变化与层间物种的电子性质相关。受限的氢分子没有任何解离趋势，并且在层间空隙中采取与掺杂离子位置密切相关的位置。
