笼形水合簇中水分子对与氢键能的关系

对随机产生的一系列5¹²、5¹²6²和4³5⁶6³笼形水合簇，使用DFT/B97D/6-311++g （2d，2p）以及DFT/M052X/6-311++g （2d，2p）方法计算其能量，并讨论了这3种笼形水合簇中不同水分子对的分布与氢键的键能、笼形水合簇稳定性之间的关系。结果表明，对于3种笼形水合簇，若只考虑近邻水分子对中心水分子对的影响，则各笼形结构中只有4种氢键类型，只要确定其中1种氢键类型的个数，其他3种氢键类型的个数也可以被确定；3种笼形水合簇中氢键的平均能量和单个氢键的平均能量都随n（1221）值的增大而增加；但是在n（1221）值相同时，不同笼形水合簇中单个氢键的平均值几乎相同；当n（1221）值不同时，不同笼形水合簇的氢键网络能量出现重叠，说明笼形水合簇稳定性与4种氢键类型的分布值之间无严格对应关系。

The relationship between water molecule pairs and hydrogen bond energy in cage hydration clusters

A series of cage hydration clusters 521 5¹², 592 5¹²6² and 501 4³5⁶6³ were randomly generated. The energy of hydrogen bonding is the difference between the energy of these cages and the loose cage. Their energies were calculated using the DFT/B97D/6-311++g(2d, 2p) method and the DFT/M052X/6-311++g(2d, 2p) method in the Gaussian09 package. The relationships between the distribution of different water molecule pairs, the energy of hydrogen bonds and the stability of the cage hydration clusters in the three cage hydration clusters are discussed. The results show that in the three cage hydration clusters, if we only considered the influence of the neighboring water molecules in the central water molecule pair, there are only four hydrogen bond types in each cage structure. When the number of one of the hydrogen bond types is fixed, the numbers of the others will also be fixed. The average energy of hydrogen bonds and single hydrogen bonds in the three cage-type hydrated clusters increase with increasing value n(1221). However for the same value of n(1221), the average energy of single hydrogen bonds is almost equal in the three different cages. When the values of n(1221) are different, the energies of the hydrogen bond network overlap for different cage hydration clusters, so there is no strict correspondence between the stability of the cage hydration clusters and the distribution of four types of hydrogen bonds.