Gas In A Divalent Cation Water Cluster Complex Structural Features Of The Theoretical Research

The clusters consisting of NH₄⁺ and water are systematical studied by using the B3LYP/6-31 +G(d) theoretical level of the density functional theory in this thesis. Configurations of the clusters are full optimized and then frequency computations are carried out under the configurations optimized in order to confirm the minimal point and transition state. It is shown that the first stationary structure is linear hydrogen bonding NH₄⁺ and water in clusters, the second is bifurcated structure, the third is trifurcated structure. On the basis of the hypothesis force field, it is confirmed that there are respectively 3, 5, 2, 6, 6, 4, 2 isomers when NH₄⁺ combines water from one to seven. In all configurations, the clusters of linear hydrogen bonding NH₄⁺ and water are easiest formed. Compared with other clusters, it is concluded that the average distance between ion and oxygen in water of the first water layer is increasing, due to the bond repulsive action between ion and water, along with the number of water from one to four. As to the clusters including five and six water, binding action between ion and water of the first water layer is strengthened. Because the number of water of the first water layer does not change, the result is only that increasing water is combined with the first water layer by the hydrogen bonding form.