INVITATION
to a TALK by
Ass. Prof. Bum Suk Zhao
School of Nano-Bioscience and Chemical Engineering
UNIST – Ulsan National Institute of Science and Technology, South Korea
Grazing incidence thermal energy atom scattering
Monday, May 6th 2024, 16:15 h
Location: Ernst Mach Lecture Hall, 2nd floor, Boltzmanngasse 5
Hosted by: Markus Arndt
Abstract:
The wave nature of particles postulated by de Broglie one hundred years ago was confirmed for atoms and molecules by Estermann and Stern in their scattering experiments of He and H2from a crystal LiF surface. Since then, scattering of thermal energy atoms of a few tens meV from surfaces has been used in surface science to study surface structures, surface phonons, particle-surface interactions, and surface changes over time. Grazing incidence thermal energy atom scattering (GITEAS) at a surface offers a unique approach that can complement conventional TEAS, akin to the relationship between X-ray scattering and grazing incidence X-ray scattering. The lower effective energy and longer wavelength toward the surface for GITEAS make it more sensitive to weak interactions and less responsive to surface roughness. As a result, GITEAS has become valuable for studying the dispersive interaction of atoms with a surface. Furthermore, atom optics with GITEAS can find applications in, e.g., quantum sensing and Helium microscopy. In this presentation, I will introduce the efforts of our group to establish GITEAS. As basic studies, we have investigated the three reflection mechanisms in GITEAS: classical reflection, quantum reflection, and multiple edge-diffraction reflection. Additionally, we have reported the comprehensive peak-width analysis, aspects of Babinet’s principle and reciprocity theorem, and Rayleigh-Wood anomaly in GITEAS. We also have applied GITEAS to probe the dispersive interaction of the atoms or molecules with various surfaces and have found various atom optical components.
