# Applying molecular theory to steady-state diffusing systems

## Abstract

Predicting the properties of nonequilibrium systems from molecular simulations is a growing area of interest. One important class of problems involves steady-state diffusion. To study these cases, a grand canonical molecular dynamics approach has been developed by Heffelfinger and van Swol [J. Chem. Phys. 101, 5274 (1994)]. With this method, the flux of particles, the chemical potential gradients, and density gradients can all be measured in the simulation. In this paper, we present a complementary approach that couples a nonlocal density functional theory (DFT) with a transport equation describing steady-state flux of the particles. We compare transport-DFT predictions to GCMD results for a variety of ideal (color diffusion), and nonideal (uphill diffusion and convective transport) systems. In all cases, excellent agreement between transport-DFT and GCMD calculations is obtained with diffusion coefficients that are invariant with respect to density and external fields. (c) 2000 American Institute of Physics.

- Authors:

- Department of Computational Biology and Materials Technology, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)
- Department of Parallel Computational Sciences, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

- Publication Date:

- OSTI Identifier:
- 20216010

- Resource Type:
- Journal Article

- Journal Name:
- Journal of Chemical Physics

- Additional Journal Information:
- Journal Volume: 112; Journal Issue: 17; Other Information: PBD: 1 May 2000; Journal ID: ISSN 0021-9606

- Country of Publication:
- United States

- Language:
- English

- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DIFFUSION; TRANSPORT THEORY; MOLECULES; DENSITY; THEORETICAL DATA

### Citation Formats

```
Frink, Laura J. Douglas, Thompson, Aidan, and Salinger, Andrew G.
```*Applying molecular theory to steady-state diffusing systems*. United States: N. p., 2000.
Web. doi:10.1063/1.481376.

```
Frink, Laura J. Douglas, Thompson, Aidan, & Salinger, Andrew G.
```*Applying molecular theory to steady-state diffusing systems*. United States. doi:10.1063/1.481376.

```
Frink, Laura J. Douglas, Thompson, Aidan, and Salinger, Andrew G. Mon .
"Applying molecular theory to steady-state diffusing systems". United States. doi:10.1063/1.481376.
```

```
@article{osti_20216010,
```

title = {Applying molecular theory to steady-state diffusing systems},

author = {Frink, Laura J. Douglas and Thompson, Aidan and Salinger, Andrew G.},

abstractNote = {Predicting the properties of nonequilibrium systems from molecular simulations is a growing area of interest. One important class of problems involves steady-state diffusion. To study these cases, a grand canonical molecular dynamics approach has been developed by Heffelfinger and van Swol [J. Chem. Phys. 101, 5274 (1994)]. With this method, the flux of particles, the chemical potential gradients, and density gradients can all be measured in the simulation. In this paper, we present a complementary approach that couples a nonlocal density functional theory (DFT) with a transport equation describing steady-state flux of the particles. We compare transport-DFT predictions to GCMD results for a variety of ideal (color diffusion), and nonideal (uphill diffusion and convective transport) systems. In all cases, excellent agreement between transport-DFT and GCMD calculations is obtained with diffusion coefficients that are invariant with respect to density and external fields. (c) 2000 American Institute of Physics.},

doi = {10.1063/1.481376},

journal = {Journal of Chemical Physics},

issn = {0021-9606},

number = 17,

volume = 112,

place = {United States},

year = {2000},

month = {5}

}