Fizika Nizkikh Temperatur: Volume 25, Number 8-9 (August 1999), p. 976-986 ( to contents , go back )
Localization of vibrations nearly the impurity atoms in semi-infinite and infinite linear chains
M. A. Mamalui, E. S. Syrkin, and S. B. Feodosyev
B. Verkin Institute for Low Temperature Physics and Engineering, National Academy of Sciences of Ukraine, 47, Lenin Ave., 310164, Kharkov, Ukraine
(Received April 1, 1999 )
For a semi-infinite linear chain with an end impurity and for an infinite linear chain with an interstitial or substitutional impurity (a triatomic defective cluster in the general case), exact analytical expressions are derived for local densities of atoms of the system in relation to the distance to a defect and to the defect parameters (variations in mass and force constants). The defect parameter dependences of the conditions for formation of local vibrations and of the amplitudes of vibrations of these frequences (i.e the character their damping) are determined for different atoms of the system. Exact analytical expressions which determine the threshold values of the parameters as a function of separation between impurity atom and end of the chain are derived and analysed.