The vibrational behavior of vacancies in body-centered cubic metals was considered by using the Green's function method. In particular, the local densities of states of the first- and second-nearest neighbors of the vacancy were calculated. These were the atoms which were most affected by a defect. The local density of states of the first-nearest neighbors was shifted to lower frequencies, as compared to host spectra, while the local spectra of second-nearest neighbors in Mo and W were little affected by the defect. In a-Fe, the second-nearest neighbor spectrum shifted to higher frequencies. In all 3 metals, the local spectra of neighbors of the vacancy did not exhibit any resonance or localized modes. The local spectra of neighbors were used to calculate formation entropy and thermal mean-square displacements. The values which were obtained for the formation entropy by using the local density of states approach were similar to those found by using other methods.

Vibrational Density of States of First and Second Neighbours of Vacancies in BCC Metals. S.S.Pohlong, P.N.Ram: Journal of Physics - Condensed Matter, 1998, 10[48], 10901-8