Portal de Periódicos da CAPES

Vibrational spectra of binary disordered linear chains with short-range order

1974; American Physical Society; Volume: 10; Issue: 6 Linguagem: Inglês

10.1103/physrevb.10.2159

0556-2805

Ronald D. Painter, William M. Hartmann,

Mechanical and Optical Resonators

We consider the generation of binary disordered linear chains with short-range order by using the theory of Markov processes. We generate second-order Markov chains in which specific correlations are introduced to first- and second-nearest neighbors. We find the density of vibrational states for several second-order chains in which one of the two kinds of atoms is twice as heavy as the other, but the nearest-neighbor force constants are unchanged. Properties of these spectra can be related to the chain structures, but pair correlation functions do not provide an adequate measure of structure to specify details of the spectra. We derive an expression for the integrated density of states at special frequencies for second-order chains and find that chains with quite different structures may have identical integrated spectra at all special frequencies.