▎ 摘　　要

A series of two-dimensional sheets of hexagonal carbon rings, with hydrogens around the edges, has been investigated computationally as models for graphene. Bond distances were optimized at the density functional SVWN/6-31G* level, and then HF/STO-5G electrostatic potentials and local ionization energies were calculated on the systems' surfaces. The potentials above the carbon rings are uniformly weakly negative, especially in the central portions of the systems. Overall, the analysis suggests low reactivity for these regions. On the other hand, certain of the outermost C-C bonds are expected to have considerable double bond character. (C) 2001 Elsevier Science B.V. All rights reserved.