Dynamics of molecule-induced electron emission from surfaces

We now know that when molecules interact with a solid, especially a semiconductor or a metal, the excitation of electrons can be an important energy dissipation pathway. This means that the dynamics of molecules interacting at solid surfaces cannot be described simply by mechanical forces, where molecular motion is dictated by a single electronically adiabatic potential energy surface, even when dissipation to phonons is correctly described. New dissipative dynamics, electronic friction being a simple example, are essential to understanding this topic. By microscopic reversibility, it is also clear that hot electrons in solids can supply energy to molecular adsorbates, for example activating reaction centers. Such issues are the concern of the field of electronically non-adiabatic molecule–surface interactions, which is reviewed in this article. Experimental work aims to control molecular degrees of freedom such as vibration, rotation and translation and observe each type of motion's role in exciting electron hole pairs and even in driving electron emission. This review aims to stimulate further experiments to shed light on the electron dynamics upon molecule–surface interaction as well as to trigger theoretical calculations to explain current and predict future findings.