Berlin 2024 – scientific programme
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O: Fachverband Oberflächenphysik
O 80: Scanning Probe Microscopy: Light Matter Interaction at Atomic Scales II
O 80.6: Talk
Thursday, March 21, 2024, 11:45–12:00, MA 041
Electron and phonon driven mobility of the ammonia clusters adsorbed on a copper surface — •Prashant Srivastava1, Daniel Miller2, and Karina Morgenstern1 — 1Chair of physical chemistry I, Ruhr University of Bochum, Germany — 2Department of Chemistry, Hofstra University, United States2Department of Chemistry, Hofstra University, United States
Understanding molecular kinetics induced by interfacial energy transfer at metal-molecule interfaces is important in molecular electronics and battery research. We explore the ultrashort laser pulse-induced mobility of ammonia clusters adsorbed on a copper surface at a single-molecule level by a combination of low-temperature scanning tunneling microscopy with an adjoined femtosecond laser and density functional theory. The diffusion of single molecules and desorption of molecules from clusters above an area of 1.35 nm2 is observed at laser fluences below 0.390 mJ/cm2. At higher laser fluences, single molecules desorb. In this talk, we present fluence-dependent changes in the ammonia coverage to understand the excitation mechanism. We discuss how the ammonia molecules and clusters are excited by electrons and phonons in a fluence range from 0.117 mJ/cm2 to 0.625 mJ/cm2. The study contributes to a control of molecular kinetics via interfacial energy transfer.
Keywords: ammonia; interfacial energy transfer