Ultrafast molecular transport on carbon surfaces: The diffusion of ammonia on graphite

2017/09/30 by Anton Tamtögl, Marco Sacchi, Irene Calvo‐Almazán +7 · 13 citations
Chemical Engineering · Chemistry · Materials Science · Physics and Astronomy · #Adsorption #Advanced Chemical Physics Studies #Ammonia #Ammonia Synthesis and Nitrogen Reduction #Analytical Chemistry (journal) #Atomic physics #Chemical physics #Chemistry #Diffusion #Diffusion process #Fick's laws of diffusion #Graphene research and applications #Graphite #Materials science #Molecule #Optics #Organic chemistry #Physical chemistry #Physics #Thermodynamics #Ultrashort pulse #cond-mat.mtrl-sci #van der Waals force

paper · pdf · doi:10.1016/j.carbon.2017.09.104

published in Carbon 126, 23-30 (Elsevier BV)

openalex publication_date 2017/09/30 · arxiv created 2017/10/02 · arxiv updated 2017/10/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06

Abstract

We present a combined experimental and theoretical study of the self-diffusion of ammonia on exfoliated graphite. Using neutron time-of-flight spectroscopy we are able to resolve the ultrafast diffusion process of adsorbed ammonia, NH₃, on graphite. Together with van der Waals corrected density functional theory calculations we show that the diffusion of NH₃ follows a hopping motion on a weakly corrugated potential energy surface with an activation energy of about 4 meV which is particularly low for this type of diffusive motion. The hopping motion includes further a significant number of long jumps and the diffusion constant of ammonia adsorbed on graphite is determined with D=3.9 ⋅ 10^-8~m² /s at 94 K.

Citations

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