Critical Asymptotic Behavior of Correlations in a Simple Liquid

We consider a representation of the total and the direct correlation functions in a liquid in terms of the corresponding spectral densities. Analysis of the spectral density properties reveals a mechanism responsible for changing the analytic properties of the Fourier transform of the correlation function and its asymptotic behavior in the critical domain. We show that the well-known restrictions imposed on possible values of the critical asymptotic exponent follow from this mechanism.