(111a) Use of the Ornstein-Zernike Percus-Yevick Equation to Extract Interaction Potentials From Pair Correlation Functions | AIChE

(111a) Use of the Ornstein-Zernike Percus-Yevick Equation to Extract Interaction Potentials From Pair Correlation Functions

Authors 

Wang, Q. - Presenter, University of Tennessee
Keffer, D. J. - Presenter, University of Tennessee, Knoxville
Nicholson, D. M. - Presenter, Oak Ridge National Laboratory
Thomas, B. - Presenter, Eastman Chemical Company


In this work, we test the ability of the Ornstein-Zernike equation in the Percus Yevick approximation (OZPY) to generate interaction potentials from pair correlation functions (PCFs) of monatomic and diatomic Lennard-Jones fluids. The PCFs are generated by solving OZPY equation (monatomic fluid) and Molecular Dynamics (MD) simulations (diatomic fluid). Since the interaction potentials are inputs in the OZPY method and the MD simulation, the extraction of the potential from the PCFs using OZPY is a test of self-consistency. This test is necessary if the procedure is to be used to generate coarse-grained (CG) potentials from PCFs. We find that the procedure is completely self-consistent for the monatomic fluid in the whole range of densities studied (reduced density up to 0.55, under reduced temperature 2.0). In the diatomic case, we find that the procedure is generally self-consistent under both low and high densities, although there is a systematic deviation at high densities. The method is able to reproduce the two parameters (ε and σ) of the input Lennard-Jones potential model to within about 1%. This CG potential generating procedure can be straightforwardly extended to more complicated molecules.

Acknowledgments

This research was supported by the Eastman Chemical Company. This research project used resources of the National Institute for Computational Sciences (NICS) supported by NSF under agreement number: OCI 07-11134.5. This work was also supported by the STAIR program at the University of Tennessee, funded by NSF under agreement number: DGE 0801470.