Comparative study of the ReaxFF and potential models with density functional theory for simulating hexagonal ice

Abstract

This paper compares ReaxFF, SPC/E, TIP4P/2005 and TIP4P/Ice with Density Functional Theory (DFT) to identify which one should be used to model both the microstructures and mechanical properties of large size hexagonal Ice (Ih) over a long time scale (~10−9–10−6 s). According to the model performances with regards to determining the microstructure, surface energy and fracture toughness, the limitations and validities of ReaxFF and the three other potential models are discussed. It is found that hydrogen bond density determines the surface energy on the same surface. TIP4P/Ice has the smallest error and the ReaxFF force field has the largest error, up to 27.21% for the aforementioned quantities. If only modeling the microstructure of ice Ih, TIP4P/2005 and SPC/E are the most suitable water models. Moreover, the secondary prism face 112¯0, with the lowest hydrogen bond density and fracture toughness, is the first cleavage plane of ice Ih. The primary prism face 1¯100 is the second cleavage plane, as shown by the surface energy and fracture toughness results of DFT and molecular dynamics (MD).