Amorphous silica modeled with truncated and screened Coulomb interactions: A molecular dynamics simulation study

Antoine Carre (1) , Ludovic Berthier (1) , Juergen Horbach , Simona Ispas (1) , Walter Kob (1)

1 LCVN - Laboratoire des colloïdes, verres et nanomatériaux

We show that finite-range alternatives to the standard long-range BKS pairpotential for silica might be used in molecular dynamics simulations. We studytwo such models that can be efficiently simulated since no Ewald summation isrequired. We first consider the Wolf method, where the Coulomb interactions aretruncated at a cutoff distance r_c such that the requirement of chargeneutrality holds. Various static and dynamic quantities are computed andcompared to results from simulations using Ewald summations. We find very goodagreement for r_c ~ 10 Angstroms. For lower values of r_c, the long--rangestructure is affected which is accompanied by a slight acceleration of dynamicproperties. In a second approach, the Coulomb interaction is replaced by aneffective Yukawa interaction with two new parameters determined by a forcefitting procedure. The same trend as for the Wolf method is seen. However,slightly larger cutoffs have to be used in order to obtain the same accuracywith respect to static and dynamic quantities as for the Wolf method.

Domaines: Mécanique statistique [cond-mat.stat-mech]

Antoine Carre, Ludovic Berthier, Juergen Horbach, Simona Ispas, Walter Kob. Amorphous silica modeled with truncated and screened Coulomb interactions: A molecular dynamics simulation study. Journal of Chemical Physics, 2007, 127 (11), pp.114512. ⟨10.1063/1.2777136⟩. ⟨hal-00364974⟩