Ryabinkin Ilya G, Izmaylov Artur F
Department of Physical and Environmental Sciences, University of Toronto Scarborough , Toronto, Ontario M1C 1A4, Canada.
Chemical Physics Theory Group, Department of Chemistry, University of Toronto , Toronto, Ontario M5S 3H6, Canada.
J Phys Chem Lett. 2017 Jan 19;8(2):440-444. doi: 10.1021/acs.jpclett.6b02712. Epub 2017 Jan 6.
An accurate description of nonadiabatic dynamics of molecular species on metallic surfaces poses a serious computational challenge associated with a multitude of closely spaced electronic states. We propose a mixed quantum-classical scheme that addresses this challenge by introducing collective electronic variables. These variables are defined through analytic block-diagonalization applied to the time-dependent Hamiltonian matrix governing the electronic dynamics. We compare our scheme with a simplified Ehrenfest approach and with a full-memory electronic friction model on a 1D "adatom + atomic chain" model. Our simulations demonstrate that collective-mode dynamics with only a few (two to three) electronic variables is robust and can describe a variety of situations: from a chemisorbed atom on an insulator to an atom on a metallic surface. Our molecular model also reveals that the friction approach is prone to unpredictable and catastrophic failures.
准确描述分子在金属表面的非绝热动力学，面临着与众多紧密间隔的电子态相关的严峻计算挑战。我们提出了一种混合量子 - 经典方案，通过引入集体电子变量来应对这一挑战。这些变量是通过对控制电子动力学的含时哈密顿矩阵应用解析块对角化来定义的。我们在一维“吸附原子 + 原子链”模型上，将我们的方案与简化的埃伦费斯特方法以及全记忆电子摩擦模型进行了比较。我们的模拟表明，仅包含少数（两到三个）电子变量的集体模式动力学是稳健的，并且可以描述多种情况：从绝缘体上的化学吸附原子到金属表面的原子。我们的分子模型还表明，摩擦方法容易出现不可预测的灾难性失败。
