Abstract

In non-equilibrium quantum dynamics arising in chemcial physics, often an atom, a molecule, or electrons (the “system”) is / are embedded in an environment (or “bath”), which gives rise to energy and phase relaxation. This affects the spectroscopic response of the system, its reactivity, and its dynamics in general. In this talk I will mostly consider the special case of atoms or molecules in contact with solid surfaces, which play a role in surface spectroscopy and surface photochemistry. Here we focus on fundamental aspects of energy and phase relaxation by adsorbate-phonon (for all surfaces) and / or adsorbate-electron / hole pair coupling (for metal surfaces). A “system plus bath” approach to multidimensional quantum dynamics will be followed, treated either by a multidimensional time- dependent Schrödinger equation (using, for example, the Multi Configurational Time Dependent Hartree (MCTDH) method or an “exactly” solvable, so called Bixon-Jortner model), or by a re- duced description in which an open-system Liouville von Neumann is solved instead. Issues of Markovianity, finite temperature effects, spectroscopy, and optical controllability of / in open sys- tems will be addressed. Besides model problems, various concrete examples of energy and phase relaxation of adsorbed or scattering species at surfaces will be considered, but also spectroscopy in molecular crystals, and, if time permits, laser-driven electron dynamics in condensed phases.