Adiabatic energy loss in hyperthermal h atom collisions with Cu and Au: A basis for testing the importance of nonadiabatic energy loss

Nonadiabatic energy transfer from the translational motion (T) of a molecule impinging on metal surface to the metal's electrons may determine whether the molecule can lose enough energy to adsorb or react. Although it is thus relevant to heterogeneous catalysis, little is known about the strength of the coupling of T to electron hole pair (ehp) excitation. We present adiabatic ab initio molecular dynamics (AIMD) predictions of the scattering of 5 eV H-atoms from Cu and Au surfaces. Calculations of angularly resolved scattering reveal experimentally realizable conditions where only about 2% of the incidence energy is lost to the metal's phonons. Under these conditions, measurements of the translational energy loss should be able to determine the magnitude of any additional energy loss due to ehp excitation, information that is very valuable to the development of accurate theoretical descriptions of T→ehp coupling.