Modification of glycerol force Field for simulating silver nucleation under a diffusion limited condition

Molecular dynamics simulation is a powerful tool in discovering nucleation phenomena. In a simulation of silver nucleation under a diffusion limited condition, the OPLS-AA force field is used to describe the glycerol solution. But the simulation crashes after running 260 ps. The energy and trajectories analyses indicate that the contact of the H and O atoms of the neighbor hydroxyls in the glycerol molecules leads to a sharp increase of the potential energy, which results in the crash of the simulation. We propose to introduce the repulsion force between the H and O atoms by modifying the Lennard-Jones parameters of these atoms in the original OPLS-AA force field. After the modification, the crashing problem is solved. Furthermore, the density and diffusion coefficient of glycerol simulated at the modified force field show better accuracy than that obtained by by AMBER and CHARMM force fields. With the one-step L-J modified OPLS force field, the silver nucleation is simulated. With the increase of glycerol, the size distribution of silver clusters switches from the multimodal to the unimodal.