Dynamics of clusters at surfaces

Goal是团簇与表面接触的动力学过程的理论描述。我们的目标是开发一种最有效的团簇-表面相互作用的描述，以允许处理较大的团簇。我们将强调非线性区域中的电子动力学，并同时处理离子动力学。主要应用有：1)衬底对动力学过程的影响；2)团簇沉积动力学，跟踪电子发射以及电子进出衬底的动力学；3)激光激发沉积团簇后的多光子发射，发射电子的角分布和动能分布；4)沉积金属团簇中电子弛豫过程的泵浦和探测分析。研究沉积团簇的光学响应一直是探索动力学情景适当调谐的第一步。而这本身就是一项有趣的任务，尤其是底物的影响。研究的工具是依赖于时间的局域密度近似与经典离子分子动力学相耦合的密度泛函方法。目前已经有一套完整的三维TDLDA-MD代码，轴向二维的对称限制变型，以及半经典近似。

Goal is the theoretical description of dynamical processes of clusters in contact with surfaces. We aim at developing a most efficient description of the cluster-surface interaction to allow the treatment of larger clusters. We will emphasize electronic dynamics in the non-linear regime, augmented by a simultaneous treatment of ionic dynamics. Intended applications are: 1) influence of the substrate on the dynamical processes; 2) dynamics of cluster deposit, tracking electron emission as well as electron transfer into and from the substrate; 3) multi-photon emission following laser excitation of deposited clusters, angular and kinetic-energy distribution of emitted electrons; 4) pump-and-probe analysis of electronic relaxation processes in deposited metal clusters. Investigation of optical response of deposited clusters is always the first step to explore proper tuning of dynamical scenarios. And it is an interesting task of its own, particularly what the influence of the substrate is concerned. Tools for the investigations are density-functional methods at the level of the time-dependent local-density approximation coupled to classical ionic molecular dynamics. There exists already a pool of codes for that: a fully fledged three-dimensional TDLDA-MD code, a symmetry restricted variant thereof in axial two dimensions, and semi-classical approximations.