Dissociative Ionization Of Allyl Bromide In The Intense Femtosecond Laser Fields

In past three decades,with the rapid development of ultrafast laser technology,it becomes possible that the light-matter interaction can be observed in femtosecond or attosecond time scale,and lots of new phenomena and mechanism have been predicated and observed in theory calculation and experiment respectively,such as: high harmonic generation(HHG),multi-photon ionization(MPI),dissociative ionization(DI)and Coulomb explosion(CE)etc.To investigate the reaction dynamic processes of molecules in the field precisely,some new particle detection techniques have been invented,such as time-of-flight(TOF),velocity mapping imaging(VMI),DC-slice imaging(DCSI)and cold target recoil ion momentum spectrometer(COLTRIMS)etc.Based on these techniques,researchers have studied the ultrafast dynamics of the molecule ionization,dissociation and Coulomb explosion in attosecond time scale and pico-meter spatial scale.Due to the key role of halogenated alkane molecules in atmospheric physics and environment protection field,the investigation of these molecules in an intense laser field has attracted more and more attention.In this thesis,utilizing the home-built three-dimension slice imaging reaction microscope,we explored the ionization,dissociation and Coulomb explosion processes of gaseous molecular allyl bromide in 800 nm and 400 nm femtosecond laser fields,the details as follows.1.The ionization and dissociation of allyl bromide molecule in 800 nm and 400 nm laser fields has been studied by the time-of-flight technology.By means of the analysis of the dependence of ion yield with laser intensity and the quantum chemical calculation,the dissociation along C-Br and C-C was discussed,and the dissociative ionization processes of the parent molecule ions were also investigated.2.The non-resonant excited dissociation and Coulomb explosion processes of allyl bromide molecule in 800 nm and 400 nm laser fields have been studied by the DC-sliced imaging technology.The sliced images of related fragment ions have been obtained and the corresponding kinetic energy releases(KERs)have been extracted and fitted.The different Coulomb explosion channels were identified based on the momentum conservation law.