Most objective information on the structure of short-range order in liquid metals can be derived from diffraction studies with the use of X-ray or synchrotron radiation, and electron and neutron beams [1]. These studies provide the possibility of experimentally determining the so-called structure factor S(k) of the melt, the Fourier transform of which gives the radial atomic distribution function g(r) (Fig. 1.1). The g(r) function has a sense of the density of probability to find an atom of the melt at a distance r from the given atom, i.e. it characterizes the time-averaged short-range order in the atomic arrangement.