第一性原理对强电场下孤立水分子的理论研究

摘要

In this paper, we detailed calculate the isolate water molecular structure and electric dipole moment under a strong electric field by the first-principles methods. The results showed that: isolated water molecule structure and electric dipole small changes in the strong electric field. Oxygen-hydrogen (OH) bond length in a water molecule increases slightly and the angle between the two OH bond decreases. On the other hand, electric dipole moment which becomes larger with the increase of the electric field. In a strong electric field, water molecules structure and parameters are different from normal water state. These changes can bring error in relevant theoretical simulation of water molecules under a strong electric field. The calculations require a higher accuracy in water molecular dynamics simulation must make some modifications.%用第一性原理方法对强电场下孤立水分子的结构，电偶极矩做了详细计算。计算结果表明：孤立水分子结构和电偶极矩在强电场下发生微小变化。水分子中的氢氧键的键长有微小的增加，两个氢键夹角变小；其电偶极矩随电场增加而变大。在强电场下，水分子参数与与常态下的水分子参数不同，使用常态下水分子模型研究强电场下有关水分子模拟问题必然会带来误差。处理计算精确度较高的分子动力学模拟问题时必须对水分子模型做一些修正才能使用。