Electron Momentum Spectroscopy Study Of Molecular Core Orbitals And Some Fundamental Chemical Physics Issues

Electron momentum spectroscopy (EMS), which could give both of the electron binding energies and the electron momentum density distributions at the same time, has been developed to be a powerful tool for the investigation of electronic structure and electron ionization mechanics and become one of the leading fields of physics, chemistry, biology, material and pharmaceutical sciences.The work of the dissertation could be divided into two parts. One is the EMS study of molecular core orbitals and some fundamental chemical physics issues and the other is the development of the data acquisition system.The EMS measurement of the chemical shift is reported for the first time. By studying the N1s core orbitals of N2O which are of more than 400 eV binding energies and three orders of magnitude lower than the valence orbitals in the (e, 2e) cross-sections, the EMS theory of core orbitals is evaluated and a more direct and pronounced manifestation of the chemical shift than Electron Spectroscopy for Chemical Analysis (ESCA) is also demonstrated. ESCA gives the information of the chemical shift and chemical environment only by the differences of binding energies, however, EMS could deliver the information by both of the differences in binding energies and wavefunctions, the heart and soul of physics and quantum chemistry.The dissertation also presents the EMS study of the complete valence orbitals of the pharmaceutical molecules and Freon molecules. The electron structures of these molecules are obtained. Furthermore, we get a lot of valuable results in some fundamental chemical physics issues, such as electron correlation effects, distorted wave effects, orbital ordering and evaluation of the quantum chemistry calculation methods and so on.The dissertation also gives a detailed description of the data acquisition system. The hardware of the system is based on USB interface and thesoftware, including more than 8,000 lines, is developed with the Visual Basic and Visual C++ language. The software system has a friendly interface as well as good readability and high efficiency. Furthermore, it has a brief and complete algorithm design on auto-controlling, spectrum displaying and off-line data analyzing. Moreover, the auto alarm function is embedded in the software, which greatly increases the reliability and efficiency of the experimental data.