hydrogen;
deuterium;
atomic hydrogen;
molecular hydrogen;
carbon nanomaterials;
nanographite;
armchair edge;
zigzag edge;
surfaces and interfaces;
nanofabrications;
electron states (localized);
tunnelling;
atom;
molecule and ion impact;
neutron scattering;
thermal desorption spectroscopy;
density functional theory;
D O I:
10.1016/j.ssc.2004.08.043
中图分类号:
O469 [凝聚态物理学];
学科分类号:
070205 ;
摘要:
We investigate and discuss how hydrogen behaves at the edges of a graphite sheet, in particular the armchair edge. Our density functional theory-based calculations results show that, in contrast to the zigzag edge [W.A. Di (n) over tildeH. Nakanishi, H. Kasai, T. Sugimoto, T. Kondoe, e-J. Surf. Sci. Nanotech. 2 (2004) 77. [25]], regardless of orientation, there is an activation barrier hindering H-2 dissociation at the armchair edges. And once they do get dissociatively adsorbed at the armchair edges, we find that it would be extremely hard to desorb the H from their adsorption sites at the armchair edges. Furthermore, we also found that, consistent with our earlier conclusions [W.A. Di (n) over tildeo, Y. Miura, H. Nakanishi, H. Kasai, T. Sugimoto, J. Phys. Soc. Jpn. 72 (2003) 1867. [24]], it is unlikely that we would find a whole H-2 in between plain graphite sheets. (C) 2004 Elsevier Ltd. All rights reserved.