Study On The Photodissociation Dynamics Of Alkyl Bromide

The contents of this dissertation mainly include:introduction to the background knowledge of photodissociation dynamics, introduction to the time-sliced ion-velocity map imaging techniques and ion-velocity map imaging apparatus, study on the photodissociation dynamics of2-bromohexane at～234nm by ion-velocity map imaging technique. We obtain the correlative dynamics parameters by measuring the speed distribution and the angular distribution of the dissociation products Br and Br*, and then we determine the photodissociation channel and reaction mechanism. At last, we compare and summarize the relevant dynamics parameters of several alkyl bromides.Introduction to the background knowledge of photodissociation dynamics:Firstly, make a brief overview of photodissociation dynamics, and then describe the main contents of study on photodissociation dynamics, the types of photolysis reactions, physical information can be obtained through study on photodissociation dynamics, techniques, background, significance of study on photodissociation dynamics and my research motivation, research system in this dissertation.Techniques and apparatus of the time-sliced ion-velocity map imaging:The experiment in this dissertation was performed on a set of ion velocity imaging apparatus built by group of Professor Yang Chen. Firstly, we introduce the development process of the time-sliced ion-velocity map imaging technology, experimental procedure, slicing methods, velocity resolution and its application. It also presents the experimental apparatus of the ion-velocity map imaging, which including the vacuum chamber part, the injection section, the light source, the signal detection and data collecting part. Finally, we introduce the performance test to achieve its optimal performance before using this set of ion-velocity map imaging apparatus on our experimental study.Study on the photodissociation dynamics of2-bromohexane at～234nm:Time-sliced ion-velocity map imaging technique was used to study the photodissociation dynamics of2-bromohexane molecular at～234nm. Relative quantum yield of Br (2P3/2) at～234nm for the photodissociation of2-bromohexane is derived to be0.961. From the map images we obtain the speed and angular distribution of fragments Br and Br*. The speed distributions of the products can be fitted with two Gaussian functions, respectively come from two independent photolysis reaction channels of the photodissociation for2-bromohexane at～234nm. Wherein the high and low kinetic energy channel is corresponded to the dissociation along the C-Br bond stretching vibration mode and the exclusion mode of C-Br bond stretching vibration coupled with bending vibration respectively. In addition, we also discuss the contributions of the states3Q0,3Q1, and1Q1 to the dissociation fragments of2-bromohexane at～234nm. At last, we compare and summarize the relevant dynamics parameters of several alkyl bromides.