| Study on the applications of plasmas involved in the fields of physics, chemistry and engineering is always an important topic for theoretical and experimental research. Being one of the most important resources of cold plasmas, the dielectric barrier discharge (DBD) plays a significant role in ozone synthesis, UV source (10-400 nm) and the prompting power supply of high-power CO2 laser and so on. Because of the vagueness on plasmas chemical process in applications mentioned above, many scientific groups have carried researches on the intermediates produced by DBD, such as Langmuir probes, in situ spectroscopy and mass spectroscopy. Small molecules and radicals such as NO, CO, OH, CH3 etc can be detected by in situ spectroscopy, while for large ones with bigger distribution function and small rotational constant, the spectral lines overlap and become structureless, so it is difficult to measure quantitatively and analyse qualitatively. For mass spectroscopy the neutrals are ionized through suitable ionization method, and the ions are detected by mass spectrometer (MS). The familiar MS includes quadrupole MS and time-of-flight MS. Due to the limitation of tunable wavelength range of laser, only part of neutrals can be detected by laser ionization. This treatise studies the composition of plasmas in ethanol, n-propanol and iso-propanol discharge with synchrotron radiation and molecular beam mass spectroscopy. The experimental results can provide valuable data on theoretical research for them and can supervise the exploitation of raw and processed materials for new pattern fuel cell. It has four chapters:In chapter 1, the knowledge about plasmas and dielectric barrier discharges is introduced in detail. The chapter consists of two parts: Firstly, the definition of the plasma is presented, along with the ionization degree and the temperature of plasma. The plasmas are classified as thermal plasmas and cold plasmas, and their sources are described briefly. Secondly, the chemical diagnostics methods of plasmas are interpreted, such as Langmuir probe, conventional spectroscopic methods and mass spectrometry. Finally we introduce the extensive applications of cold plasmas.A brief description is given on the definition and the configurations of the dielectric barrier discharge (DBD). Physical processes of discharge are analyzed in detail and its applications in industry and daily life are presented.In Chapter 2, it describes the experimental setup which can be used to research the plasmas chemistry by VUV synchrontron radiation photoionization. Main characteristics and advantages possessed in the application fields by synchrotron radiation source are described. The configuration and parameters of beamline are presented in detail. The structures and principles of both molecular beam and reflectron time-of-time mass spectrometer are described in detail. A description is given on our experimental endstation and the ion signal detection.In Chapter 3, all the neutrals formed from the dielectric barrier discharge of ethanol are presents through VUV photoionization and molecular beam mass spectrometer. The ionization thresholds of intermediates are accurately obtained from photoionization efficiency curves, and then all the neutrals are identified unambiguously compared with IEs from literature. In the same way, isomers are distinguished from different onsets observed from PIE curves.In Chapter 4, the neutrals produced from dielectric barrier discharge of n-propanol and iso-propanol are presented in detail through VUV photoionization and molecular beam mass spectrometer. The different intermediates of the two propanol produced by the discharge are investigated, and we find the contact relationship between the intermediates and the configuration of propanol samples. In the discharge of n-propanol, the ethenol (m/e=44), propenol and propanal (m/e=58) are detected, while in iso-propanol discharge the ethenol and acetaldehyde (m/e=44) and propenol and acetone (m/e=58) are observed.
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