Chlorophenol And O-chlorophenol - Water Clusters Multiphoton Ionization

In recent years, study of hydrogen clusters is being attached more and more importance to. As a mutual action force among molecules, hydrogen bond plays an important role in many scientific problems. Without it, fusion, energy transfer and chemical reaction cannot be carried out. Particularly in bio-molecules contains a large amount of hydrogen bonds. The study of hydrogen clusters can help people understand these processes from a relatively simple system. With the development of industry and society, the increasingly serious problem of environmental pollution has severely challenged people's daily life and health. The compound of chlorophenol, represented by o-chlorophenol, is widely used. But meanwhile the compound of chlorophenol is released to nature as an industrial waste, which produces an extremely harmful pollutant. Therefore, the study of the compound of chloropheno has become a hot issue recently. The thesis, with the technology of laser mass spectra and ultrasonic molecular bundle, conducts its study on how o-chlorophenol/water clusters come into being and how multiphoton ionization of o-chlorophenol. With Gaussian03 calculating procedure, the thesis optimizes geometric structures of some ions—gained in the experiment, on the level of B3LYP/6-31G(d) and calculates their energy as well as vibration frequency.The thesis begins with an introduction of the experiment and theoretical calculating methods adopted in the experiment. Then it centers on description of the components of laser mass spectra technology—the principle of multiphoton ionization and TOF mass spectra. In the thesis there is a quite minute presentation about Gaussian03 calculating procedure, especially the specific calculating methods and base level.On a device of TOF mass spectra, the multiphoton ionization experiment of o-chlorophenol/water clusters is finished under the effect of 355 run laser and has formed the chart of TOF mass spectra. The experimental devices and methods are presented in detail. Result of the experiment and chart of TOF mass spectra are analyzed. The thesis focuses its study on the process of multiphoton ionization and dissociation of o-chlorophenol-water clusters and finds that ionization process mainly appears in o-chlorophenol molecules of this cluster, then dissociates and results in the production of non-proton products. Besides, the possible reason why non-proton products cannot be found is given. Through changing delay of laser relative pulse valve and laser intensity, the experiment discovers: as the delay of laser relative pulse valve increases, signal intensity of cluster ions first goes up then down; as laser energy increases gradually, not only does the signal intensity of original cluster ions becomes stronger, but there also constantly emerge new cluster ion signals.With Gaussian03 calculating procedure, the paper optimizes the possible structures of some cluster ions on the level of B3LYP/6-31G(d) base level. Some geometric parameters of stable structures are found out. Through analyzing the structural features, one phenomenon is found: with the increase of the number of H₂O molecules in the cluster, the distance between Hydrogen atom and hydrogen-giving in the hydrogen bond is growing farther. By contrasting structures of C₆H₅ClO-(H₂O)₃⁺, it is found that cluster structure of the tree structure is the most stable. On the level of B3LYP/6-31G(d) base level, calculating the frequency of stable structures leads to IR spectra, which indicates that the most powerful IR mode majorly stems from expansion and shrinkage vibration of hydrogen atom in hydrogen bond.With the same devices and similar methods, multiphoton ionization experiment of o-chlorophenol is carried out under the effect of 355 run laser. By analyzing the experiment result and spectra chart, the channel of multiphoton ionization and dissociation of o-chlorophenol is acquired. By changing delay of laser relative pulse valve and laser intensity, it is found that signal intensity of ions has something to do with delay of laser relative pulse valve as well as laser intensity. By optimizing neutral particles and the structure of matrix ions with the help of Gaussian03 calculating procedure on the level of B3LYP/6-31G(d)base level, some geometric parameters of stable structures are obtained, A contrasting analysis is made on structural features of the two. Through Gaussian03 calculating procedure, IR spectra of the two is achieved and analyzed.The study on o-chlorophenol/water clusters and o-chlorophenol multiphoton ionization provides information for studying the compound of chlorophenol and gains further knowledge on structures and vibration frequency of hydrogen cluster.