The simple points charged(SPC) three-site model was adopted for H_2O molecule,the potassium ion was treated as hard sphere,and a rigid four-site model was adopted for the nitrate ion.

• 水分子采用简单点电荷(SPC)三节点模型,钾离子被看作带电硬球,硝酸根离子采用刚性四节点模型,同时考虑节点间的库仑长程作用和L-J相互作用,对库仑长程作用采用EWALD求和方法进行计算。