H Atom Adsorption on a Silicate Surface: The (010) Surface of Forsterite
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- 作者：S. Garcia-Gil ; D. Teillet-Billy ; N. Rougeau ; V. Sidis
- 刊名：The Journal of Physical Chemistry C
- 出版年：2013
- 出版时间：June 20, 2013
- 年：2013
- 卷：117
- 期：24
- 页码：12612-12621
- 全文大小：444K
- 年卷期：v.117,no.24(June 20, 2013)
- ISSN：1932-7455
文摘
We present a first-principles computational study of the interaction of an H atom with the (010) surface of forsterite (Mg2SiO4). Periodic DFT-GGA calculations (PBE) are carried out using the SIESTA code with core pseudopotentials and TZP localized basis sets. Potential energy curves are determined for the approach of the H atom toward different sites of the surface: atop, near, or in between the O, Mg, and Si atoms. An outer adsorption well is found for all investigated sites; it is deepest (162 meV) at a so-called 鈥渄isplaced Mg鈥揙 bridge鈥?position. The binding at this well is of the 鈥渨eak chemisorption鈥?鈥渟trong physisorption鈥?type. An inner stronger chemisorption well (670 meV deep) exists exclusively near an O site but not strictly atop. Depending on the path, we find activation barriers (25鈥?70 meV high) against chemisorption, the lowest of these occurs for the top O site. General trends of the computed interaction energies qualitatively agree with the QM/MM results of Goumans et al. [lass="ref" href="#cit11">Mon. Not. R. Astron. Soc.2009, 393, 1403], but adsorption binding energies and barrier heights differ significantly.