Dissociative Photoionization of β-Pinene: An Experimental and Theoretical Study
Dissociative Photoionization of β-Pinene: An Experimental and Theoretical Study
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DOI：
10.1255/ejms.1304
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发表时间：
2014-12
影响因子：
1.3
通讯作者：
Maoqi Cao;Jun Chen;W. Fang;Yuquan Li;Shaolin Ge;Xiaobin Shan;Fu-yi Liu;Yujie Zhao;Zhenya Wang;Liu-si Sheng
中科院分区：
文献类型：
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作者：
Maoqi Cao;Jun Chen;W. Fang;Yuquan Li;Shaolin Ge;Xiaobin Shan;Fu-yi Liu;Yujie Zhao;Zhenya Wang;Liu-si Sheng
利用飞行时间质谱仪，在8.00 eV~15.50 eV的可调真空紫外光照射下，研究了β-Pinene分子的光致电离和解离电离。以电子碰撞为电离源，实验测得的电离能(IE)为8.60 eV，与G3MP2方法的理论值(8.41 eV)不符。由效率谱得到了准确的β-Pinene等效谱IE(8.45±0.03 eV)，与CBS-QB_3方法的理论值(8.38 eV)符合得很好。在实验观察和理论计算相结合的基础上，我们解释了初级碎片离子与β-Pinene阳离子的解离途径。大多数解离途径是通过解离前的重排反应进行的。我们还确定了这些异构化过程的过渡态和中间体的结构。
We investigated the photoionization and dissociation photoionization of the β-pinene molecular using time-of-flight mass spectrometry with a tunable vacuum ultraviolet source in the region from 8.00 eV to 15.50 eV. The experimental ionization energy (IE) value is 8.60 eV using electron impact as the ionization source, which is not in good agreement with theoretical value (8.41 eV) with a G3MP2 method. We obtained the accurate IE of β-pinene (8.45 ± 0.03 eV) derived from the efficiency spectrum, which is in good agreement with the theoretical value (8.38 eV) of the CBS-QB3 method. We elucidated the dissociation pathways of primary fragment ions from the β-pinene cation on the basis of experimental observations in combination with theoretical calculations. Most of the dissociation pathways occur via a rearrangement reaction prior to dissociation. We also determined the structures of the transition states and intermediates for those isomerization processes.