Response properties at the dynamic water/dichloroethane liquid–liquid interface

ABSTRACT

We present a novel approach for calculating the static dielectric permittivity profile of a liquid–liquid interface (LLI) from molecular dynamics simulations. To obtain well-defined features, comparable to those observed at solid–liquid interfaces, we find it essential to reference to the instantaneous liquid–liquid interface rather than the more commonly used average Gibbs interface. We provide a coarse-grained approach for the practical definition of the instantaneous interface and present numerical results for the prototypical water/1,2-dichloroethane system. These results show that the parallel components of the dielectric permittivity tensor can be accurately extracted. In contrast, the perpendicular component does not converge to the correct bulk value at large distances from the LLI, highlighting a flaw in the regularly applied coarse-graining procedure.

GRAPHICAL ABSTRACT

KEYWORDS:

• Dielectric permittivity tensor
• instantaneous liquid–liquid interface
• molecular dynamics simulation

Acknowledgments

Computational resources have been partially provided by HPC projects at the Leibniz Rechenzentrum (LRZ), Garching.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Harald Oberhofer http://orcid.org/0000-0002-5791-6736

Karsten Reuter http://orcid.org/0000-0001-8473-8659

Christoph Scheurer http://orcid.org/0000-0002-7227-8672

Additional information

Funding

Z. L. is thankful for the support from the China Scholarship Council [201306190104].