Calculation of relaxation functions: A new development within the Mori formalism

The problem of expanding the correlation functions into continued fractions is considered in the light of a Mori-type formalism. First, we examine the techniques available in the literature for extracting the parameters of the Mori chain from the moments; then, on the basis of physical considerations, we provide a new surprisingly simple and efficient technique and discuss its significance. Some examples are given to illustrate the elegance and the convenience of our procedure.