Hydrogen bonding in liquid water at 1 GPa : Molecular dynamics simulation study of TIP4P/2005 water model

Liquid water structure and dynamics at 1 GPa and in the temperature range 300-230 K is investigated here using molecular dynamics simulations of TIP4P/2005 water model. A recently reported hydrogen bond criterion is used to collect the hydrogen bonded water molecules. In the temperature range studied average local coordination was X7.3 and fraction of 3, 4 and 5 hydrogen bonded water molecules were 10, 60 and 20%, respectively. For 4 hydrogen bonded water, 2-Donor-2-Acceptor geometry is always preserved. For 5 hydrogen bonded water, fraction of acceptor bonds are more than the donors because donor bonds are more strained compared to the acceptor ones. Comparing the local orientational ordering in oxygens and hydrogens with ices V, VI and VII, we note striking similarities between ice V and high pressure liquid water. Dynamics show that intensities of bending and streching modes increase with decrease in temperature.

Automated summary

The structure and dynamics of liquid water at 1 GPa and temperatures ranging from 300-230 K were investigated using molecular dynamics simulations of the TIP4P/2005 water model. The study revealed proportions of hydrogen bonded water molecules and average local coordination numbers were temperature-dependent. Additionally, similarities between high pressure liquid water and ice V were noted, along with an increase in intensities of bending and stretching modes as temperature decreased.