The Effects of Attractive Interaction on Viscosity in Undercooled Kob–Andersen Liquids

We present the effects of interatomic attraction on liquid fragility from atomistic calculations. Shear viscosity is sensitive to thermodynamic conditions as well as numerical setups, and deeper undercooling substantially increases the viscosity of the Kob–Andersen liquids due to the reduced atomic mobility. The attractive force plays a major role in determining the viscosity and liquid fragility in the undercooled region, and the viscosity in the presence of attractive interactions more rapidly increases as the temperature drops, showing a super-Arrhenius behavior of a fragile liquid. On the contrary, a liquid of purely repulsive atoms is found to be a strong liquid. The computational cost nearly doubles for the undercooled liquids along with the attractive interaction as the correlation of dynamic properties persists longer due to higher viscosity.