Department of Chemistry, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven, Belgium.
J Phys Chem Lett. 2022 Sep 15;13(36):8477-8483. doi: 10.1021/acs.jpclett.2c01969. Epub 2022 Sep 2.
Dissociative electron attachment, that is, the cleavage of chemical bonds induced by low-energy electrons, is difficult to model with standard quantum-chemical methods because the involved anions are not bound but subject to autodetachment. We present here a new computational development for simulating the dynamics of temporary anions on complex-valued potential energy surfaces. The imaginary part of these surfaces describes electron loss, whereas the gradient of the real part represents the force on the nuclei. In our method, the forces are computed analytically based on Hartree-Fock theory with a complex absorbing potential. molecular dynamics simulations for the temporary anions of dinitrogen, ethylene, chloroethane, and the five mono- to tetrachlorinated ethylenes show qualitative agreement with experiments and offer mechanistic insights into dissociative electron attachments. The results also demonstrate how our method evenhandedly deals with molecules that may undergo dissociation upon electron attachment and those which only undergo autodetachment.
离解电子俘获，即低能电子诱导的化学键断裂，用标准量子化学方法难以模拟，因为涉及的阴离子未被束缚而是会自动离解。我们在此提出一种新的计算方法，用于模拟复值势能表面上的临时阴离子动力学。这些表面的虚部描述了电子损失，而实部的梯度代表了原子核上的力。在我们的方法中，基于含复吸收势的 Hartree-Fock 理论，通过解析计算力。对二氮、乙烯、氯乙烷和五氯至四氯代乙烷的临时阴离子的分子动力学模拟与实验定性一致，并为离解电子俘获提供了机理见解。结果还表明，我们的方法如何公平地处理可能在电子俘获时发生离解的分子以及仅发生自动离解的分子。
