Liquid Na-K alloy: triplet correlation function in the long-wavelength limit

Triplet correlation functions for liquid Na---K alloy, in the long-wavelength limit, have been calculated with the partial structure factors derived by taking the square-well potential as a perturbation over the hard-sphere potential. The present structure factors generate the experimental compressibilities from the Kirkwood-Buff general formula while the compressibilities derived from the conformal solution theory structure factors are higher than the experimental ones