An Experimental Investigation On Resonance Enhanced Multiphoton Ionization /Dissociation Dynamics Of Acetone And Dimethyl Sulfide

Atoms, molecules or radicals can be excited to a specific intermediate state by absorbing m photons, then ionized through absorbing another one more photons. The ion yield can be increased drastically in the resonant absorption, comparing with that in non-resonant absorption. This process is called Resonance-Enhanced Multiphoton Ionization (REMPI). As a spectral detection method with high sensitivity and resolution, REMPI technique plays an important role in the fields of analysis chemistry, state-resolved detection of molecules and radicals, photoionization and photo-dissociation dynamics, isotope separation and combustion diagnose. So it is concluded that REMPI is very effective in both the basic and application research fields.In this paper, the investigation on the dynamics of multiphoton dissociation/ionization of Acetone and dimethyl sulfide has been carried out by using REMPI-TOF-MS technique. It is proposed that the main dissociation channel is the photoionization of parent molecule firstly in the range of 280-286.5nm, then followed by photodissociation of parent ion and the further photodissociation or photoionization of the fragment, which is not totally consistent with the results presented by other research group. Our experimental results are helpful in understanding the detailed MPI processes of Acetone and dimethyl sulfide. This paper consists of five chapters. The main contents are listed as following.In chapter one, a brief introduction of the techniques of REMPI, MPI, and their development, characters and application fields are presented.In chapter two, the basic principles of multiphoton dissociation/ionization of molecular including the selection rule of the...