Local density of states of 〈110〉-split interstitials and their neighbors in molybdenum

In a previous paper we studied the dynamics of self-interstitial atoms in bcc metals and calculated the local density of states of the 〈110〉 dumbbell in Mo using a Green's-function method. In this paper, we calculate the local density of states of neighbors of the dumbbell which affect the properties of the irradiated metal significantly. The local density of states of the neighbors show the same well-known resonance and localized modes shown by the dumbbell spectrum. However, the amplitude of vibrations of neighbors in the resonant modes is, in general, very small so that only the spectrum of the closest neighbor in the (11{}0) plane shows clearly all the resonant modes found with the dumbbell spectrum. The result is discussed in the light of M\"ossbauer measurements of irradiated Mo⁵⁷Co. Contrary to earlier expectations, the vibrational modes of the M\"ossbauer atom located at a substitutional site nearest to a dumbbell atom do not explain the observed reduction in the Debye-Waller factor.