MD simulations are performed using the Large-scale atomic molecular massively parallel simulator (LAMMPS) software. The velocity-Verlet algorithm is used with a time step of 1 fs. Periodic boundary conditions are applied in all three Cartesian directions. The SHAKE constraint algorithm is included to satisfy the equilibrium length values for all covalent bonds involving the H-atoms. The non-bonded interactions include both the Lennard-Jones potential with a 12 Å cut-off and long-range Coulombic interactions. Geometric mean mixing rules are used to represent the cross interactions between different atom types. The long-range electrostatic interactions are solved in reciprocal space using the particle-particle particle-mesh (PPPM) algorithm 81 with a relative force accuracy of 10 -5 .