Photodissociation of allene studied by time-of-flight mass spectrometry and dispersed fluorescence spectroscopy

• Main Authors: Tseng, Gi-Chen, 曾基城
• Other Authors: Chen Yit-Tsong
• Format: Others
• Language: zh-TW
• Published: 1998
• Online Access: http://ndltd.ncl.edu.tw/handle/81988447965006252945

碩士 === 國立臺灣大學 === 化學系 === 86 === The ionic and luminous products of allene excited with a single focused laser beam at 193 nm are detected by a time-of-flight mass spectrometer and a dispersed emission spectrometer, respectively. The major ionic products detected are C3+, C2+, and C+. For the emission spectra, the C2 Swan system, C2 Mulliken system, CH transitions, and an atomic line corresponding to the C transition are the major features. The vibrational population distribution of the C2(d3Pg) state is found to be inverted with respect to thermal distributions. Laser power dependence of each product is measured and a kinetic model is developed to investigate the ionization and dissociation mechanisms. The experimental data infer that phtodissociation of C3Hn (n = 1-4) at 193 nm is more favored than multiphoton ionization within the laser flux used (< 2.7E26 photons cm-2 s-1). While for the C3, multiphoton ionization and multiphoton dissociation are both feasible.