Structure and nanoscale dynamics of hydrogen containing molecules at carbon materials & interfaces

Description

The high scattering cross section of helium and neutron beams towards hydrogen provides experimental access to the structure and dynamics of hydrogen containing molecules[1] at carbon materials, including e.g. the hydrogenation of graphene[2]. Lineshape broadening upon inelastic scattering from surfaces can be used to determine the nanoscopic motion of atoms and
molecules[1]. While e.g. electronic transitions at surfaces are accessible with optical spectroscopy, the diffusion of molecules occurs in the pico- to nanosecond regime and the study of these dynamical processes is a unique and challenging problem, requiring both sub-nanometre spatial resolution and
fast temporal resolution.

I will present experimental results about the motion of a number of hydrogen containing molecules on carbon surfaces[3-5], allowing us to establish accurately the surface energy landscapes that would template e.g. molecular self-assembly and giving insight into the dominant modes of motion along
the diffusion pathways. Due to the low energy of the probing beam, we are able to study the dynamics of delicate adsorbates such as water[1]. Our results about the microscopic motion of H2O on graphene, provide a unique molecular perspective on barriers to ice nucleation at surfaces.

References
[1] A. Tamtögl et al., Nat. commun., 11, 278 (2020).
[2] E. Bahn et. al. Carbon 114, 504 (2017)
[3] I. Calvo-Almazán et al., Carbon 79, 183 (2014).
[4] I. Calvo-Almazán et al., J. Phys. Chem. Lett. 7, 5285 (2016).
[5] A. Tamtögl et al. Carbon 126, 23 (2018).

Period	25 Aug 2020 → 28 Aug 2020
Event title	NanoteC: Carbon Nanoscience and Nanotechnology
Event type	Conference
Conference number	20
Location	Guildford, United KingdomShow on map
Degree of Recognition	International