Elucidation of Electron Ionization Induced Fragmentations of Adenine by Semiempirical and Density Functional Molecular Dynamics
Elucidation of Electron Ionization Induced Fragmentations of Adenine by Semiempirical and Density Functional Molecular Dynamics
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DOI：
10.1021/jp5096618
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发表时间：
2014-12-11
影响因子：
2.9
通讯作者：
Grimme, Stefan
中科院分区：
文献类型：
--
作者：
Bauer, Christoph Alexander;Grimme, Stefan
基于随机和第一性原理的分子动力学方法，研究了腺嘌呤在70 eV电子电离时的气相裂解途径。我们在我们的计算中没有采用预想的碎片化通道，其模拟标准电子电离质谱（EI-MS）条件。观察到的反应比较以及丰富的实验和理论数据可用于这个重要的核酸构建块。重现了腺嘌呤实验质谱中的所有显著峰。此外，从我们的模拟中获得的碎片离子的连通性至少部分地同意从以前的实验研究选择性同位素标记的腺嘌呤的结果。此外，我们能够分配的非环状结构，熵的青睐，并没有提出在非动态量子化学研究之前的分解产物，这是自动从我们的分子动力学程序的结果。从各种条件下的模拟可以看出，即使在低的内部过剩能量下，大多数碎裂反应（
The gas phase fragmentation pathways of the nucleobase adenine upon 70 eV electron ionization are investigated by means of a combined stochastic and first-principles based molecular dynamics approach. We employ no preconceived fragmentation channels in our calculations, which simulate standard electron ionization mass spectrometry (EI-MS) conditions. The reactions observed compare well to a wealth of experimental and theoretical data available for this important nucleic acid building block. All significant peaks in the experimental mass spectrum of adenine are reproduced. Additionally, the fragment ion connectivities obtained from our simulations at least partially concur with results from previous experimental studies on selectively isotope labeled adenines. Moreover, we are able to assign noncyclic structures that are entropically favored and have not been proposed in nondynamic quantum chemical studies before to the decomposition products, which result automatically from our molecular dynamics procedure. From simulations under various conditions it is evident that most of the fragmentation reactions even at low internal excess energy (