Density Functional Theory Study Of Alkaline Metal Nitrogen Binary Clusters

Alkali metal and compounds have a wide range of applications in production and life, people research more and more their physicochemical properties. But so far, the study of Alkaline metal nitrogen clusters are still very limited. In this work, tructures and properties of nitrogen compounds (K₃N)_n(n=1⁵) clusters and tructures and properties of azides (MN₃)n(n=1⁵, M=K, Na) clusters are studied by using DFT/B3LYP with 6-311G* basis sets.In c hapter 2, we optimized the structures of the(K₃ N)_n (n=1⁵)clusters. then the bond property, charge distribution, vibrational property, and stability of the most stable isomers of these clusters were calculated. The calculated results give that the stablest isomers of (K₃N)_n(n=1⁵) clusters are changing gradually from planar structure to Three-Dimensional structure, (K₃N)4,(K₃N)5 are Layered structure similar to the crystal; the coordination number of N atoms are usually 5 or 6; the natural charges of N atom and K atom are about -1.6078 e and +0.5495 e, respectively; between the K atoms and N atoms exist a strong ionic bond; the dynamic stabilities of (K₃N)4 cluster is higher than that of other clusters.In c hapter 3, we optimized the structures of the(NaN₃ )n (n=1⁵)clusters, then the bond property, charge distribution, vibrational property, and stability of the most stable isomers of these clusters were calculated. The calculated results give that azido in clusters h as linear structure, the most optimized NaN₃ has linear structure, the most optimized (NaN₃)n(n=2³) have plane structure of ring structure, and the most optimized (NaN₃)n(n=4⁵) have the plane or space structures composed by the most optimized NaN₃ cluster. The bond lengths for the most of the optimized (NaN₃)n(n=1⁵) clusters are about 0.1154⁰.1196 nm for N-N and 0.2053⁰.2443 nm for N-Na. The middle N atoms of azido show positive, the N atoms at both ends of azido show negative, and the N atoms effected with Na atoms directly show more negative. There is a ionic bond between the Na atoms and N atoms. The whole strongest vibrational peak of the IR spectra of the most optimized (NaN₃)n(n=1⁵) clusters lies in 2180 ²240cm-1,and the vibrational mode is anti-symmetric stretching vibration of N-N bonds in azido. The dynamic stabilities of (NaN 3)3 cluster is higher than that o f other clusters.In c hapter 4, we optimized the structures of the(KN₃ )n (n=1⁵)clusters, and the charge distribution, bond property, vibrational property, and stability of the most stable isomers of these clusters were calculated. The calculated results give that azido in clusters h as linear structure, the most optimized K N₃ has linear structure, the most optimized (KN₃)n(n=2³) have plane structure of ring structure, and the most optimized (KN₃)n(n=4⁵) have the plane or space structures composed by the most optimized KN₃ cluster. The bond lengths for the most of the optimized (KN₃)n(n=1⁵) clusters are about 0.1156⁰.1196 nm for N-N and 0.2357⁰.2868 nm for N-K. The middle N atoms of azido show positive, the N atoms at both ends of azido show negative, and the N atoms effected with K atoms directly show more negative. There is a ionic bond between the K atoms and N atoms. The whole strongest vibrational peak of the IR spectra of the most optimized (KN₃)n(n=1⁵) clusters lies in 2180 ²230cm-1, and the vibrational mode is anti-symmetric stretching vibration of N-N bonds in azido. (KN₃)3 cluster is more stable than other clusters.