Molecular orbital imaging beyond the first monolayer: Insights into the pentacene/Ag(110) interface

Understanding the molecular geometry at interfaces is not only of importance for optimizing contact properties but also sets the basis in energy alignment in multilayer samples. Here we present a method to determine the tilt angle of molecular compounds by a combination of the orbital imaging technique with photoemission matrix element calculations. By simulating different tilt angles of isolated molecules and comparing the resulting photoemission intensity distribution with momentum maps measured on molecular multilayers, one is able to determine the molecules' tilt angles for each separate layer independently from one another.