Molecular Dynamical Simulation of Ice Phase Transition: Ice Ih to High-Density Amorphous

We put 5kbar and 12kbar on perfect ice Ih lattice at 77K and 180K. After 30000 simulation steps (in units of 10^-15s), high-density amorphous ice is formed. Four-site simple-pair potential TIP4P is used
for molecular interactions and the rigid molecular model is employed. Phase transition processes are fitted by an exponential function, and different phase transition times τ are obtained from O-O radial distribution functions (366 and 359fs for 77K and 180K) and O-O-O angle distribution functions (126 and 116fs for 77K and 180K).