Electrofreezing of water in molecular dynamics simulation accelerated by oscillatory shear

We present a study of the effect of oscillatory shear on the crystallization of supercooled water in nonequilibrium molecular dynamics simulations of simple water models. [The TIP4P model has been used throughout; calculations using the extended simple point charge (SPC/E) model were checked for consistency and gave qualitatively the same results.] The application of a planar Couette flow field alone did not result in crystallization but in combination with a static electric field different isomorphs of ice emerged depending on the state of the system. At high pressures (3 - 5 kbar) the oscillatory shear substantially speeded up the formation of the conjectured ice polymorph (ice XII). At ambient pressures lower density systems could be forced to order in situations where hitherto the application of the electric field alone has not resulted in ordering. These results suggest that this method will be very useful in exploration of the fluid-solid boundaries of the phase diagram of models for water.