This document describes the fruitful collaboration of Dr. Volker Deringer from the University of Cambridge, UK, and Dr. Miguel Caro, from the Aalto University, Finland, which started through a HPC-Europa3 transnational access visit. The collaboration has resulted directly in three high-impact journal publications and was motivated by the different skills which together enabled carrying out ground-breaking research on industrially and scientifically important amorphous carbon films. The work has also advanced the simulation methods in general. The visits have secured a strong international link and active collaboration between the two groups. The role of HPC-Europa3 in the collaboration is discussed.