▎ 摘　　要

Geometrical and electronic structures of a hydrogen-added graphene have been investigated by means of density functional theory (DFT) and direct molecular dynamics (MD) methods. A graphene composed of 19 benzene rings was examined as a model of finite-sized graphene. The hyperfine coupling constants (hfcc's) of hydrogen atoms on graphene were calculated to be similar to 63 G in the bulk region and 20-5 G in the edge region of graphene, indicating that the hfcc of hydrogen atoms is strongly dependent on the bonding site. The excitation energies of hydrogen added graphene were calculated to be 1.28, 1.54, and 1.60 eV, which were lower than that of graphene without hydrogen atoms (2.24 eV). The first electronic transition was assigned to an excess electron transfer band from a defect hydrogen site to the bulk region of graphene. The electronic states and thermal behavior of hydrogen atoms interacting with graphene are discussed on the basis of theoretical results. (C) 2010 The Japan Society of Applied Physics