为研究α-蒎稀的光电离解离机制, 采用同步辐射光电离质谱, 在7.9~15.5 eV能量范围内研究了α-蒎稀的紫外光电离解离, 对α-蒎稀的电离解离能及其碎片离子的出现势进行了理论分析.实验测得光电离效率曲线, 从光电离效率曲线中获得α-蒎稀C10H16的电离能和碎片离子C9H+13, C7H+10, C3H+6 及CHH+3的出现势.用Gaussian 03理论方法计算了C10H16和主要的光解离碎片的总能量, 用高级能量计算方法计算了C10H16的电离能和部分碎片离子的出现势及主要的解离通道的离解能.根据实验和理论计算结果, 分析了产生碎片离子的主要的解离通道.分析表明实验测得的结果与理论计算提出的C10H16的光解离通道获得的解离能符合得较好.

To explain the mechanism of ionization of the α-pinene (C10H16), the VUV dissociative photoionization of C10H16 in an energy region of 7.9~15.5 eV has been investigated with a mass-spectrometer method photoionization mass spectroscopy using synchrotron radiation, the dissociation energies and the appearance energies for its fragment ions were predicted. The ionization energy of C10H16 and appearance energies for its fragment ions, C9H+13, C7H+10, C3H+6 and CH3+, were determined with photoionization efficiency spectroscopy. The total energies of C10H16 and its main photofragments were calculated using Gaussian 03 program. The ionization energy of C10H16, appearance potentials for its fragment ions, and the dissociation energies to produce them were predicted using high accuracy energy model. The dissociation energies of some possible dissociation channels to produce those fragment ions were determined based on comparison of determined appearance energies and energies predicted with the Gaussian-03 calculations. According to the results, the experimental dissociation energies were in reasonable agreement with the calculated dissociation energies of proposed photodissociation channels of C10H16.