The microcanomical ensemble of liquid water was studied by using molecular dynamics simulation at temperatures ranging from 150 to 376K. The structure and the thermodynamic properties were investigated. Flexible water-water interaction potential MCYL was used in the simulation. The effects of temperature on the geonetry of water molecules and on the structure of liquid water were averaged over both the time and space. The analysis of the radial distribution functions shows that there are 2~3 hydrogen bonds formed for each water molecule, and the molecule in liquid form acts both as donor and receptor. The studies on the vibrational spectra indicate that network structure of water at lower temperature mingt turn into the small chuster structure as temperature goes higher.

Key words: WATER, THERMODYNAMIC PROPERTIES, AB INITIO CALCULATION, MOLECULAR DYNAMICS, POTENTIAL FUNCTIONS