Studies On The Dissociative Ionization And The Dissociative Double Ionization Of BrCH₂CH₂Cl In Femtosecond Laser Field

The interaction of intense laser pulses with matter remains still to be an important problem and receives more and more attentation in modern laser physics. The development of ultrashort pulse laser technology promotes in-depth studies on the laser interaction with atoms and molecules,and more and more new physical phenomenas are observed, including of high-order harmonic generation (HHG), above threshold ionization (ATI), multiphoton ionization (MPI), dissociative ionization (DI) and dissociative double ionization (DDI), High intensity and non-resonant excitation of ultra-short femtosecond laser greatly improve the efficiency of multi-photon absorption, the dissociative ionization and dissociative double ionization, and the population on highly excited states of atoms and molecules. Moreover, halogenated hydrocarbon compounds are the important model molecule for investigating the photodissociation and photoionization, and their interaction with the femtosecond laser attracts widespread attention, and become one of the most hot research field.In this thesis, we have studied the interaction the bromine-dichloroethane molecule with the intense femtosecond laser field, and its photodissociation dynamics has been deeply explored.1. The time of flight mass spectra of the bromine-dichloroethane molecule is determined with the excitation of different intense femtosecond laser pulses. The measured results show that the intensity dependence of the C-Cl bond breaking ion signal (Cl+and CH2CH2Br+), the C-Br one (Br+and CH2CH2Cl+) and the C-C one (CH2Br+and CH2C1+) is different, respectively. Combined with DC sliced ion velocity mapping technique, it can be concluded that the CH2Br+and CH2Cl+ions come from the dissociative double ionization, however the Cl+, CH2CH2Br+, Br+and CH2CH2Cl+come from both the dissociative ionization and the dissociative double ionization;2. The velocity mapping images of the photolysis fragments, including of Cl+, Br+, CH2CH2Cl+, CH2CH2Br+, CH2Br+and CH2Cl+are measured by direct current slice imaging technique with the excitation of different intense femtosecond laser pulsers. Their translational energy distribution and angular distribution have been measured, and their photodissociation dynamical processes have been discriminated. Here, their dissociative double ionization is firstly investigated by direct current slice imaging technique.