FREQUENCY-DEPENDENT THERMODYNAMIC RESPONSE FUNCTIONS FROM COMPUTER-SIMULATIONS

Information about frequency dependent thermodynamic properties such as the isocoric specific heat, (c) over tilde(v) (omega), or the isobari c thermal expansion coefficient, <(alpha)over tilde>(P)(omega), is imp ortant for understanding the dynamics of supercooled liquids. A specia l fluctuation-dissipation (FD) theorem is developed. It establishes th e connection between equilibrium fluctuations in a microcanonical ense mble and response functions of macroscopic entities upon perturbation of energy or volume. Using this theory, information of all thermodynam ic response functions can be calculated from one molecular dynamics si mulation. (C) 1998 Elsevier Science B.V. All rights reserved.