ANALYTICAL METHODS FOR CALCULATION OF INTERATOMIC POTENTIALS THROUGH THE DATA ON THE SHORT-RANGE ORDER IN ALLOYS

Within the framework of the high-accuracy ring approximation elaborate d by the authors (Chepulskii R V and Bugaev V N 1998a, b J. Phys.: Con dens. Matter 10 7309-26, 7327-48) in the context of the modified therm odynamic perturbation theory as applied to the lattice gas model, two methods are developed for calculation of the atomic interaction parame ters in binary disordered alloys with Bravais crystal lattices through the data on the atomic short-range order (SRO)-the iteration method r esulting in explicit analytical relationships and the variational meth od. Within both methods, the Fourier components of SRO parameters are used as initial data, thus, the most complete information on SRO in th e alloy is taken into account. Both the iteration and variational meth ods permit us to calculate the atomic interaction parameters for an ar bitrary number of the coordination shells as well as the Fourier compo nents of the atomic interaction potentials. It is demonstrated that bo th methods have wide temperature-concentration intervals of applicabil ity. The methods can be used under investigation not only of alloys, b ut also of other lattice systems (including low-dimensional ones, semi conductors and magnetics).