Calculation of Electron Ionization Mass Spectra with Semiempirical GFNn-xTB Methods
Calculation of Electron Ionization Mass Spectra with Semiempirical GFNn-xTB Methods
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DOI：
10.1021/acsomega.9b02011
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发表时间：
2019-09-17
期刊：
影响因子：
4.1
通讯作者：
Grimme, Stefan
中科院分区：
文献类型：
--
作者：
Koopman, Jeroen;Grimme, Stefan
在这项工作中，我们已经测试了两种不同的扩展紧束缚方法的框架内的量子化学电子电离质谱（QCEIMS）程序来计算电子电离质谱。QCEIMS方法提供了合理的第一原理计算光谱，可以直接与实验进行比较。此外，它提供了详细的洞察质谱实验的反应机制。它揭示了复杂的断裂过程中的键断裂和结构重排，是很难得到，否则。所需的准确性和计算要求成功再现质谱相关的量子化学方法进行了讨论。为了验证新的GFN 2-xTB方法，我们对15个有机，过渡金属和主族无机系统进行了模拟。主要的碎裂模式进行了分析，整个计算的光谱直接从文献中的实验数据进行比较。我们讨论的计算成本和鲁棒性（离群值）的几个计算协议。总的来说，新的，理论上更复杂的半经验方法GFN 2-xTB表现良好，鲁棒性广泛的有机，无机和有机金属系统。
In this work, we have tested two different extended tight-binding methods in the framework of the quantum chemistry electron ionization mass spectrometry (QCEIMS) program to calculate electron ionization mass spectra. The QCEIMS approach provides reasonable, first-principles computed spectra, which can be directly compared to experiment. Furthermore, it provides detailed insight into the reaction mechanisms of mass spectrometry experiments. It sheds light upon the complicated fragmentation procedures of bond breakage and structural rearrangements that are difficult to derive otherwise. The required accuracy and computational demands for successful reproduction of a mass spectrum in relation to the underlying quantum chemical method are discussed. To validate the new GFN2-xTB approach, we conduct simulations for 15 organic, transition-metal, and main-group inorganic systems. Major fragmentation patterns are analyzed, and the entire calculated spectra are directly compared to experimental data taken from the literature. We discuss the computational costs and the robustness (outliers) of several calculation protocols presented. Overall, the new, theoretically more sophisticated semiempirical method GFN2-xTB performs well and robustly for a wide range of organic, inorganic, and organometallic systems.