96-22U
96-22U
$N$-particle partial structure factors in the long-wave limit. Two-component system of hard spheres.
For an arbitrary multicomponent system the relationships for three- and four-particle partial structure factors in the long-wave limit ($S_{\gamma _{1}\gamma _{2}\gamma _{3}}(k_{i}=0)$ and $S_{\gamma _{1}\gamma _{2}\gamma _{3}\gamma _{4}}(k_{i}=0)$) are obtained on the basis of the previously derived recurrent formula. Recurrent formulae for $s$-particle correlation functions $h_{\gamma _{1}\dots \gamma _{s}}^{s}(1,2,\dots ,s)$ and distribution functions $g_{\gamma _{1}\dots \gamma _{s}}^{s}(1,2,\dots ,s)$ are deduced. For two-component system of hard spheres of diameters $\sigma _{aa}$ and $\sigma _{bb}$ the explicit expressions for $S_{\gamma _{1}\gamma _{2}\gamma _{3}}(0,0,0)$ and $S_{\gamma _{1}\gamma _{2}\gamma _{3}\gamma _{4}}(0,\dots )$ ($\gamma _{i}=a,b$) are found in the Percus-Yevick approximation, the dependences of their behaviour on the reduce density $\eta $ ($\eta =\eta _{a}+\eta _{b}$, $\eta _{i}=\rho _{i}\sigma _{ii}^{3}\pi /6$), the concentration of the $b$th species $x$ and the size ratio $\alpha $ ($\alpha =\sigma _{aa}/ \sigma _{bb}$) are demonstrated.