Charge-exchange-dependent Energy Loss of H and He in Freestanding Monolayers of Graphene and MoS2

We study the energy loss of helium and hydrogen ions after transmission through monolayers of graphene and MoS2 and compare experimental results with different computational approaches. We find a systematically higher energy loss in experiments compared to simulations by up to a factor of 2. Additionally, our results show that neutralization processes of the particles increase the kinetic energy loss, a contribution generally not included in any computational approach.