Strong Field Behavior Of Carbon Dioxide And The Excited State Dynamics Of O-dichlorobenzene

Carbon dioxide as a part of the air exists in our life, it is a indispensable condition for plant photosynthesis, it is also the cause of greenhouse effect. Chlorinated aromatic compounds are toxic substances, incinerating waste、vehicle exhaust emissions will produce chlorinated aromatic compounds which harm to the environment. Thus we select Carbon dioxide and o-dichlorobenzene molecules as the research object.Carbon dioxide is one of the simplest linear diatomic molecules. As a linear structure model molecule, the result of the electric dissociation from the model and the field induced dissociation as well as coulomb explosion of Angle distribution are different. In this thesis, we search strong field of dynamics mainly which aim at the variation of carbon dioxide and its fragment ionizing signal intensity with the change of carbon dioxide laser field intensity and polarization direction. The experiment obtain gradually disintegrate character through analyzing the time of flight mass spectrometry under the different laser intensity and polarization state, and discover that angle distribution of parent molecule ion is weakened and the angle of the atomic ion distribution is increasing obviously with the enhance of laser intensity. This phenomenon explain that due to laser intensity change geometric orientation and dynamics of the molecular orientation, different ions show different performance under different dissociation model.Chlorinated aromatic molecules widely exist in environmental issues and because of its potential toxicity are seen as hot research. O-dichlorobenzene affiliated with chlorinated aromatic molecules structure, so its studies have limitations on excited state dynamics.In order to have a thorough understanding of dichlorobenzene excited state dynamics, we use femtosecond time-resolved pump and the probe technology combined with photo electronic imaging method to search neighborhood-dichlorobenzene, detecting its first electronic excited state and high vibration excited state dynamics. Research find that when 267 nm as the pump wavelength, intersystem crossing causes the attenuation process, and when 247 nm as a pump wavelength, two attenuation channel which derived from Super fast internal conversion and Intersystem crossing are observed.