Qualitative and quantitative measurements and theoretical calculation on electron ionization of small molecules

• Main Authors: Ching-Hong Fong, 方景弘
• Other Authors: Grace. H. Ho
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/3erf34

碩士 === 國立高雄大學 === 應用化學系碩士班 === 105 === Our laboratory members had previously measured absolute branching ratios of ion products of electron ionization (EI) for 18 organic molecules with a quadruple mass spectrometer (QMS); however, they had not measured absolute EI cross sections (σ_EI^+). In this work, we used the QMS method to qualitatively and quantitatively measure σ_EI^+ of toluene, benzene and acetone using Xe or Kr as references in the threshold energy- 135 eV. This work also calculated theoretical σ_EI^+ of these molecules by BEB (Binary Encounter Bethe theory) and DM (Deutsch-Märk) models. Parameters for the BEB and DM calculation include orbital kinetic energy, kinetic energy and mulliken population, which were obtained by theoretical calculation using commercially available GaussView 5.08 and Gaussian 09W software packages. Our experimental σ_EI^+ values were compared to literature values and theoretical σ_EI^+ values derived from the BEB and DM methods. The results show that our σ_EI^+ values consist with σ_EI^+ of BEB and literature values better than those of DM’s within the experimental uncertainty.