Calculation of the Impurity‐Induced Lattice Mode Absorption

Abstract
A discussion is given of impurity‐induced lattice mode absorption occurring in the far infrared. The model used involves a diatomic linear chain with one impurity mass having a defect charge and an altered nearest neighbour force constant. The displacement of the impurity and the absorption of the perturbed lattice can be expressed in closed formulas which are evaluated numerically. For very weakly bound impurity atoms a quasi‐localized resonance behaviour occurs, which has been observed recently [12].