Physical and Life Sciences Directorate , Lawrence Livermore National Laboratory , Livermore , California 94550 , United States.
Department of Chemical Engineering , University of California , Davis , California 95616 , United States.
J Chem Theory Comput. 2018 May 8;14(5):2652-2660. doi: 10.1021/acs.jctc.8b00165. Epub 2018 Apr 11.
We detail the creation of a multicenter density functional tight binding (DFTB) model for hydrogen on δ-plutonium, using a framework of new Slater-Koster interaction parameters and a repulsive energy based on the Chebyshev Interaction Model for Efficient Simulation (ChIMES), where two- and three-center atomic interactions are represented by linear combinations of Chebyshev polynomials. We find that our DFTB/ChIMES model yields a total electron density of states for bulk δ-Pu that compares well to that from Density Functional Theory, as well as to a grid of energy calculations representing approximate H dissociation paths on the δ-Pu (100) surface. We then perform molecular dynamics simulations and minimum energy pathway calculations to determine the energetics of surface dissociation and subsurface diffusion on the (100) and (111) surfaces. Our approach allows for the efficient creation of multicenter repulsive energies with a relatively small investment in initial DFT calculations. Our efforts are particularly pertinent to studies that rely on quantum calculations for interpretation and validation, such as experimental determination of chemical reactivity both on surfaces and in condensed phases.
我们详细介绍了一种用于δ-钚中氢的多中心密度泛函紧束缚（DFTB）模型的创建，该模型使用了新的 Slater-Koster 相互作用参数框架和基于 Chebyshev 相互作用模型的排斥能（ChIMES），其中二中心和三中心原子相互作用由 Chebyshev 多项式的线性组合表示。我们发现，我们的 DFTB/ChIMES 模型对体相 δ-Pu 的总电子态密度的预测与密度泛函理论以及代表 δ-Pu(100)表面上近似 H 离解路径的能量计算网格非常吻合。然后，我们进行分子动力学模拟和最低能量路径计算，以确定(100)和(111)表面上的表面离解和亚表面扩散的能量学。我们的方法允许使用相对较小的初始 DFT 计算投资来有效地创建多中心排斥能。我们的努力对于依赖量子计算进行解释和验证的研究特别相关，例如表面和凝聚相上化学反应性的实验测定。
