中文摘要：

采用分子动力学方法模拟了温度范围为673.15～873.15 K,压力范围为22.1～131.3 MPa条件下不同状态点水的密度和自扩散系数,并与实验结果进行对比.模拟体系为256个水分子,模拟系综为等温等压系综.模拟结果表明：密度和自扩散系数的模拟预测值与实验值基本一致;密度的模拟预测值大多低于实验值,最大相对误差小于-20%;自扩散系数的模拟预测值大多高于实验值,但最大相对误差小于±20%.在缺乏实验数据时,利用单点电荷（SPC）势能模型,可采用分子动力学方法预测超临界水的密度和自扩散系数.

英文摘要：

The densities and self-diffusion coefficients of the water under different states were simulated numerically by molecular dynamics method, over a wide ranges of temperature （673.15～873.15 K） and pressures （22.1～131.3 MPa）. The results show that the simulated densities and self-diffusion coefficients are in agreement with the experimental data. For the most state points, the predicted densities are lower than the experimental values, and the predicted self-diffusion coefficients are higher than the experimental value. The maximum relative error is less than ＋20%. The density and the self-diffusion coefficient of supercritical water can be predicted by simple point charge water model through molecular dynamics simulation.