## Abstract

Examines the role of attractive forces in determining the static structure factor S(q) for simple liquids. By treating these forces in a random-phase approximation and the repulsive forces in a blip function expansion about a hard-sphere reference system the authors derive explicit results for the coefficients of q
^{2}, q
^{3} and q
^{4} in the expansion of c(q), the Fourier transform of the Ornstein-Zernike direct correlation function of a Lennard-Jones liquid, they show that the attractive forces ensure that alpha , the coefficient of q
^{2}, is negative for most thermodynamic states. This implies that even near the triple point a simple (argon-like) liquid should exhibit 'residual' Ornstein-Zernike behaviour, i.e. there should be a shallow minimum in S(q) for q approximately=0.25AA
^{-1}. The authors find that the short-range correlation length, R=(- alpha rho )
^{1/2} varies weakly with density rho and with temperature. Their calculated value for R at the critical point is in good agreement with results obtained from radiation scattering experiments on Ar and Kr near their critical points. The q
^{3} term is associated with r
^{-6} asymptotic behaviour of the interatomic potential. The authors analysis suggests that it may be possible to detect such a contribution, if it is present in a real liquid, by X-ray or neutron diffraction.

Original language | English |
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Article number | 008 |

Pages (from-to) | 2569-2579 |

Number of pages | 11 |

Journal | Journal of Physics C (Solid State Physics) |

Volume | 14 |

Issue number | 19 |

DOIs | |

Publication status | Published - 1981 |