Quantum influences in the diffusive motion of pyrrole on Cu(111)

Abstract

Classical diffusion - quantum barrier: On Cu(111), pyrrole diffuses in channels, hopping between adjacent bridge sites over a barrier above hollow sites. The motion of the center of mass can be described classically; however, the activation barrier arises from the quantum character of internal vibrational modes that are largely unexcited during the motion. The unique helium spin-echo experiment is indicated by the green sphere and arrows. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.