Fischer Eric W, Werther Michael, Bouakline Foudhil, Grossmann Frank, Saalfrank Peter
Theoretische Chemie, Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Straße 24-25, D-14476 Potsdam-Golm, Germany.
Institut für Theoretische Physik, Technische Universität Dresden, D-01062 Dresden, Germany.
J Chem Phys. 2022 Jun 7;156(21):214702. doi: 10.1063/5.0092836.
Vibrational dynamics of adsorbates near surfaces plays both an important role for applied surface science and as a model lab for studying fundamental problems of open quantum systems. We employ a previously developed model for the relaxation of a D-Si-Si bending mode at a D:Si(100)-(2 × 1) surface, induced by a "bath" of more than 2000 phonon modes [Lorenz and P. Saalfrank, Chem. Phys. 482, 69 (2017)], to extend previous work along various directions. First, we use a Hierarchical Effective Mode (HEM) model [Fischer et al., J. Chem. Phys. 153, 064704 (2020)] to study relaxation of higher excited vibrational states than hitherto done by solving a high-dimensional system-bath time-dependent Schrödinger equation (TDSE). In the HEM approach, (many) real bath modes are replaced by (much less) effective bath modes. Accordingly, we are able to examine scaling laws for vibrational relaxation lifetimes for a realistic surface science problem. Second, we compare the performance of the multilayer multiconfigurational time-dependent Hartree (ML-MCTDH) approach with that of the recently developed coherent-state-based multi-Davydov-D2 Ansatz [Zhou et al., J. Chem. Phys. 143, 014113 (2015)]. Both approaches work well, with some computational advantages for the latter in the presented context. Third, we apply open-system density matrix theory in comparison with basically "exact" solutions of the multi-mode TDSEs. Specifically, we use an open-system Liouville-von Neumann (LvN) equation treating vibration-phonon coupling as Markovian dissipation in Lindblad form to quantify effects beyond the Born-Markov approximation.
表面附近吸附质的振动动力学对于应用表面科学而言起着重要作用，同时也是研究开放量子系统基本问题的一个模型实验室。我们采用先前开发的一个模型，该模型用于研究由2000多个声子模式组成的“浴”所诱导的D:Si(100)-(2×1)表面上D-Si-Si弯曲模式的弛豫[洛伦兹和P. 萨尔弗兰克，《化学物理》482, 69 (2017)]，以沿多个方向扩展先前的工作。首先，我们使用分层有效模式（HEM）模型[菲舍尔等人，《化学物理杂志》153, 064704 (2020)]来研究比迄今通过求解高维系统-浴含时薛定谔方程（TDSE）所研究的更高激发振动态的弛豫。在HEM方法中，（许多）真实的浴模式被（少得多的）有效浴模式所取代。因此，我们能够研究一个实际表面科学问题中振动弛豫寿命的标度律。其次，我们将多层多组态含时哈特里（ML-MCTDH）方法的性能与最近开发的基于相干态的多-达维多夫-D2近似[周等人，《化学物理杂志》143, 014113 (2015)]的性能进行比较。两种方法都运行良好，在所呈现的背景下，后者具有一些计算优势。第三，我们将开放系统密度矩阵理论与多模式TDSE的基本“精确”解进行比较。具体而言，我们使用一个开放系统的刘维尔-冯·诺伊曼（LvN）方程，将振动-声子耦合视为林德布拉德形式的马尔可夫耗散，以量化超出玻恩-马尔可夫近似的效应。
