Experiment On OCS UV Photolysis Kinetics Using Time-Sliced Ion Imaging Technology

The thesis mainly discusses the reaction mechanism of carbonyl sulfide(S1D2)reaction channel near 140nm photolysis wavelength by means of time-sliced ion imaging.The state-to-state dynamics information of the scattering process is obtained by controlling the initial quantum state of the reactant and the detection of the selection of the reaction products.Firstly,we obtained the high resolution and tunable vacuum ultraviolet laser beam from 130nm to 140nm in the laboratory and used it as the excitation source of carbonyl sulfide(OCS)molecule.On the self-built cross molecular beam experimental device,the time-sliced ion imaging technology and REMPI technology are used to detect the spatial division information of the OCS dissociation,and the dynamic information of the product’s translational energy distribution and the branch ratio of different reaction channels and the anisotropic parameters are also obtained by data processing.In order to understand the OCS molecule’s mechanism of dissociation in the related photolysis,we have gained a lot of research results.Different from other photodissociation bands about OCS photodissociation dynamics discussed previously,we found that CO products were hotter(v=10-15)at the wavelength of photolysis near 140nm,and the expansion vibration mode of C-O and C-S bonds was excited in stretch vibration mode.Finally,C-S bond was broken and the product CO reside in the high vibrational state.In addition,in this photolysis wave band,the excited state of OCS corresponds to two electronic states,E1Π and F1Π,but after non-radiative transition to C1Π and B1△ electronic states,the molecule dissociated along the two electron state energy surfaces,this process is the indirect dissociation process.