Instituto de Física, Universidade Federal da Bahia, Campus Universitário da Federação/Ondina, Salvador, Bahia, Brazil.
Nanotechnology. 2010 Mar 19;21(11):115701. doi: 10.1088/0957-4484/21/11/115701. Epub 2010 Feb 22.
This work investigates, using first-principles calculations, electronic and structural properties of hydrogen, lithium, sodium, potassium and rubidium that are adsorbed, in a regular pattern, on a graphene surface. The results for H-graphene (graphane) and Li-graphene were compared with previous calculations. The present results do not support previous claims that the Li-C bond in such a layer would result in an sp(2) to an sp(3) transition of carbon orbitals, being more compatible with some ionic character for the covalent bond and with lithium acting as an electron acceptor in a bridging environment. Calculations were also performed for the Na, K, and Rb-graphene systems, resulting in a similar electronic behaviour but with a more pronounced ionic character than for Li-graphene. Energy calculations indicate the possible stability of such ad-graphene layers, with only the Li-graphene being possible to be spontaneously obtained.
本工作使用第一性原理计算研究了以规则模式吸附在石墨烯表面上的氢、锂、钠、钾和铷的电子和结构性质。与先前的计算相比，对 H-石墨烯（石墨烷）和 Li-石墨烯的结果进行了比较。本研究结果不支持先前的说法，即此类层中的 Li-C 键会导致碳原子轨道从 sp(2)到 sp(3)的转变，而是更符合共价键的一些离子特性，以及锂在桥接环境中充当电子受体。还对 Na、K 和 Rb-石墨烯体系进行了计算，得到了类似的电子行为，但与 Li-石墨烯相比，离子特性更为明显。能量计算表明，这种吸附在石墨烯上的层可能具有稳定性，只有 Li-石墨烯可能是自发获得的。
