Investigation Of Halohydrocarbon Photodissociation And The Setup Of Orientated Molecule Photodissociation

This thesis has two components: one is the investigation of halohydrocarbon photodissociation dynamics; the other is the setup of orientated molecule photodissociation.Photofragment translational spectroscopy (PTS) is an ideal tool to investigate photodissociation dynamics under collision-free conditions through which one can obtain the total center of mass (c. m.) translational distribution, angular distribution, and the branching ratios for different possible product channels by measuring the angle-resolved time of flight (TOF) spectra of photofragments. Information about photodissociation processes such as dissociative lifetime of parent molecule, the orientation of transition dipole moment, and the symmetry change of the highly excited states can be deduced from the translational energy distribution and angular distribution. In the first component of this thesis, we investigated the photodissociation dynamics of o,m,p-chlorotoluene, l-bromo-3-fiuorobenzene, 1-bromo-4-fluorobenzene, m-bromotoluene and 3-C3H5Br at 266 nm.We mainly detected the TOF and angular distribution of photofragment, and get the anisotropy parameter β and the translational energy distribution. In addition, we calculated the geometries of the ground states, the excited states and the triplet excited states, and the transition electric dipole moments. According to these, the dissociation lifetimes of some molecules are calculated.The photodissociation dynamic of isotropic molecules are studied for several decades, however, the photodissociation dynamics research of anisotropic molecules is just beginning. Because the photodissociation of anisotropic molecules provides more dynamic information, people paid attention to this technique as soon as it appeared. The second component of this thesis is about the setup of oriented molecule photodissociation and the theoretical treatment. We primarily discussed the steric distribution, the probability of electron transition and the angular distribution of photofragment of the molecules in orientation field.