Isomers And Infrared Spectroscopy Of Protonated Water Cluster

The study of clusters is a new field that emerges in recent decades. It is a new subject refersto physical, chemical and biological. Clusters have magical quantum size effect, and it causesclusters have different properties between microscopic and macroscopic object: magic number,optical properties, isomeric phenomena etc. Reserchers all over the word are interested in thestudy of clusters, and the research of clusters is entering an era of rapid development, and alsosome important research is quietly changing people’s lives. Therefore, research on clusters cannot only promote the development of basic disciplines but also promote its application value, soits prospect will be broader!H-bonding makes water has unique properties, and to study H-bonding network structuresis a basic problem. In order to explain the H-bonding network of water in molecular level, wehave researched protonated water clusters broadly. And clusters as microscopic models, givedetailed structural information. We can make clear the structure of H-bonding, becauseH-bonding environment is very vulnerable to the impact of OH stretching vibration frequencies,and therefore the study of fixed size clusters can take advantage of infrared vibrationalspectroscopy.Protonated water clusters are important in atmosphere, biological and chemical reactionsystems. One important aspect of proton in water is its high mobility, and to simulate thisprocess need the study of hydrogen motion in bulk water which has complex network. Itbecomes a challenge for chemists to research structures and IR spectroscopy of protonatedwater clusters in recent decades. By studying IR spectroscopy, we can determine the stablestructure of protonated water clusters. But now people have no direct experimental methods tomesure the structure, so our study is in the stage of theory exploration. Protonated waterclusters contain small size, medium size and large size, and every size has different structures,and most clusters contain hydrogen bonds, therefore our research will face big difficulties. DFT is a theoretical foundation of this paper. We use Gaussian09software and applyB3LYP method of density functional theory and6-311++G**basis to optimize the structuresand calculate the frequencies of H+(H20)6, and then we obtain29kinds of stable structures.Information that structures and energies offer makes us find that the structure with Zundelcation core is more stable than others. At last, by comparing the IR Synthetic photo of theoryspectrum with the experiment, we know our conclusion is reasonable.Main directory:In chapter1, We present clusters’ concept, classification, some properties; and then maindirections, progress, methods, significance of cluster research; at last is our work about thispaper.In chapter2, Related theoretic, including variation principle, Hartree approximation, Fockapproximation and DFT is showed.In chapter3, We mainly introduce Slater basis set, Gauss basis set, and Gaussian09.In chapter4, By analysis of date and image fitting, we make a conclusion that the structurewith a Zundel cation core is more stable.