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Anisole and tetrachloromethane multi-photon ionization mass spectrometry

Author: YangJianChun
Tutor: KongXiangHe
School: Qufu Normal University
Course: Physical Electronics
Keywords: TOF Multiphoton ionization Anisole Tetrachloromethane
CLC: O561.4
Type: Master's thesis
Year: 2010
Downloads: 37
Quote: 0
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Abstract

Experimental studies show that the molecules obtained by the multi-photon excitation process of energy, which is absorbed by molecules coherent photons two or more, if the absorbed photon energy at or above the ionization potential molecules, ionized molecules, in this process is often accompanied by bond breaking the molecules or ions cleaved into small pieces, so that the role of the photons and molecular multiphoton ionization process is called dissociation. Mass spectrometry is a research multiphoton ionization and dissociation effective method is the use of TOF-TOF mass spectra of organic molecules to obtain the multiphoton ionization and dissociation techniques and technology combined with TOF experiment is to study the multi-photon ionization mass spectrometry. This article is mainly for industrial and agricultural production in common organic polyatomic molecules anisole and tetrachloromethane, study the role of these two molecules in the laser and the fragmentation that occurs when the ionization channel and principles. Aromatic ether, anisole is the easiest and most representative ethers substances, is a very versatile agricultural raw materials, often used as an organic solvent and pharmaceutical intermediates. For anisole relevant reports from the very early research and has been taken by the people. Our experiment is the use of flight mass spectrometer under the action of the laser multiphoton ionization mass spectrometry anisole can get anisole dissociation channel and mechanism. This allows people to anisole ether bond structure and the functional groups of the connected nature of other important photophysical and photochemical properties of a deeper level of understanding, not only for anisole and its derivatives provide a basis, but also for other aromatic ethers study provides an important reference value. Carbon tetrachloride is a relatively common chemical raw materials, is a good organic solvent, chemical experiments often used as extraction agent. As tetrachloromethane has some toxicity will destroy the human and animal liver, and will destroy the ozone layer. So tetrachloromethane dissociation ionization process has been people's attention. This paper studies the role in determining the wavelength of the laser ionization tetrachloromethane under the dissociation process by changing conditions such as laser energy intensity analysis tetrachloromethane dissociation channel and mechanism. The main contents are four chapters. The first chapter is introductory section outlines the multiphoton ionization dissociation definition and classification and characteristics, time of flight mass spectrometry Gaussian 03 principles and research methods and theoretical basis. The second chapter is the experimental apparatus and experimental methods, this paper describes the experimental operation and data acquisition instrumentation and experimental procedures and experimental methods. Chapter III detailed analysis of the experimental anisole 355nm laser induced multiphoton ionization, dissociation get anisole belong parent ion dissociation step, anisole molecule first coherent photons become absorbed three energy-rich matrix Then ion dissociation ion pieces, eliminating methyl dissociation channel is the main channel, the other a hydrogen atom rearrangement Dissociation. Gaussian software simulation HF/6-31G basis set was C6H5OCH3 molecules and ions stable configurations calculated anisole molecular ion and its dissociation products of primary energy. The fourth chapter analyzes tetrachloromethane multiphoton dissociation ionization process is discussed tetrachloromethane multi-photon dissociation of molecular ionization channels and fragment ion dissociation channels, the results show that the main tetrachloromethane molecule is the parent molecule dissociation channels absorption of three photons reach the electronically excited state, the rapid dissociation into neutral fragment ions, which form a channel is the main channel CCl, form a C-channel is a secondary channel.

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