A simple, efficient polarizable molecular model for liquid carbon tetrachloride

Abstract

A one-site and a five-site polarizable model for liquid carbon tetrachloride (CCl₄) is presented. They are based on a non-polarizable model consisting of five van der Waals sites not carrying any partial charges. In the one-site model, a charge on a spring with a polarizability of 11.1 nm³ was attached to the carbon to make the model polarizable, while in the five-site model polarizabilities  nm³ and  nm³ were added to the carbon and chlorine atoms, respectively. Both models exactly reproduce the experimental static dielectric permittivity of 2.24 at 293 K and 1 atm. This quantity was calculated by applying a homogeneous external electric field of varying strength. The one-site polarizable model is only about 1.7 times more computationally expensive than the non-polarizable one and is compatible with the GROMOS force field. A selected set of thermodynamic, dynamic and structural quantities was calculated and compared to experiment.

Keywords:

• (bio)molecular simulation
• carbon tetrachloride
• CCl₄
• polarizable
• GROMOS
• dielectric permittivity

Acknowledgements

The authors thank Bill Swope for reminding us of the method to calculate ε(0) using an applied external electric field and Sereina Riniker for pointing out its pitfalls. This work was financially supported by the National Center of Competence in Research (NCCR) in Structural Biology and by grant number 200020-121913 of the Swiss National Science Foundation, and by grant number 228076 of the European Research Council, which is gratefully acknowledged.