抄録
The frequencies of localized and resonance modes in the honeycomb lattice are calculated. The effects of change of mass and force-constant due to impurity atom are studied. It is shown that in the case of honeycomb lattices an impurity atom brings about an s-like and two p-like localized modes, while in the case of the triangular lattices an impurity atom produces an s-like, two p-like, two d-like and an f-like modes.
