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利用真空紫外同步辐射和反射式飞行时间质谱研究了乙苯分子的光电离,通过测量母体分子的光电离质谱(PIMS)以及母体离子和主要碎片离子的光电离效率曲线(PIEs),确定了乙苯分子的电离能IE(C8H1+0)=(8.66±0.02)eV,主要碎片离子C7H7+和C6H6+的出现能分别为(10.81±0.02)和(10.99±0.02)eV;利用经验公式计算出产生碎片离子C7H7+和C6H6+需要的解离能(Ed)分别为(2.15±0.04)和(2.33±0.04)eV.结合相关的热化学参数,推算出C8H1+0,C7H7+和C6H6+的标准生成焓分别为865.5,927.2和1037.9kJ/mol.为进一步研究乙苯的大气光氧化反应机理提供了参考.
The photoionization of ethylbenzene was studied by means of vacuum ultraviolet synchrotron radiation and time of flight mass spectrometry. By measuring the photo-ionization mass spectra (PIMS) of parent molecules and the photoionization efficiency curves (PIEs) of parent ions and major fragment ions, (10.81 ± 0.02) and (10.99 ± 0.02) eV for the main fragment ions, C7H7 + and C6H6 +, respectively. The empirical formula was used to calculate the number of generated fragments The required dissociation energies for ions C7H7 + and C6H6 + were (2.15 ± 0.04) and (2.33 ± 0.04) eV, respectively. The calculated standard enthalpies of formation for C8H1 + 0, C7H7 + and C6H6 + were 865.5 , 927.2 and 1037.9kJ / mol, respectively, which provide a reference for the further study of atmospheric photooxidation mechanism of ethylbenzene.