Use of the memory function in a collinear atom/harmonic chain model

摘要

For a collinear atomhyphen;harmonic chain model we analyze the influence of the memory function on the spectral density of the velocity autocorrelation function of the atom. A numerical analysis for different memory functions is made. The Markovian limit has been checked. For memory times smaller than the parameter which characterizes the intensity of the random force, for the limited range of parameters which has been examined, there is very little difference among the three choices of memory which have been chosen. We show that as the memory time increases noticeable differences among the obtained spectral shapes appear.