一维金刚石结构晶格的非线性局域模

用多重尺度法研究了质量均匀相互作用力交替变化的原子链形成的非线性局域振动模式，这 种原子链模拟了金刚石结构晶格沿〈111〉晶向或一维分子链的振动，通过多重尺度展开分 析得出，原子位移分布服从微扰的非线性Schrdinger方程，求得了相应的定态解和传播解 ，其结果与相互作用力相同质量交替分布的另一种形式的一维双原子晶格的结果有所不同， 其原因是金刚石结构晶格的对称性相对差些. 关键词： 金刚石结构 非线性局域模 多重尺度法

NONLINEAR LOCALIZED MODES IN A ONE-DIMENSIONAL DIAMOND-STRUCTURE LATTICE

The nonlinear localized vibrational modes in an anharmonic atomic chain with uniform mass but two alternating force constants between nearest-neighbors are stud ied by means of multiple-scale expansion. This atomic chain models the vibration s of an arrow of atoms in the <111> direction of a diamond-structure lattice or a molecular chain. It is shown that the distribution of the atomic displacements is governed by a perturbed nonlinear Schrdinger equation, and both the statio nary and moving solutions are obtained. The results are somewhat different from that of the diatomic chain with uniform force constants but two alternating mass es. The reason may be that the translational symmetry of diamond-structure latti ce is comparetively lower.