▎ 摘　　要

The phonon dispersions of graphene and graphene layers are theoretically investigated within fifth-nearest-neighbor force-constant approach. Based on their symmetry groups, the number of Raman- and infrared-active modes at the Gamma point is given. Interatomic force constants are recalculated by fitting them to experimental phonon energy dispersion curves. Wavenumbers of optically active modes are presented as a function of number of layers (n). Our calculated results reproduce well the experimental data of G peak for graphene (1587 cm(-1)) and graphite (1581.6 cm(-1)) and clearly give the relation that omega(G) = 1581.6 + 11/(1 + n(1.6)). Copyright (C) 2009 John Wiley & Sons, Ltd.