Quantitative Analysis of Individual Atoms in the Channels of Beryl

Abstract The detection of single atoms with atomic resolution is a major challenge, in particular for technologically highly relevant nanoporous materials. Their nano-sized pores provide a large surface area and can also confine individual atoms and molecules, enabling the fine-tuning of catalytic performance or molecular transport properties. Previous studies employing aberration-corrected scanning transmission electron microscopy (STEM) have been limited to visualizing guest components within the pores without providing quantitative information. In this study, utilizing natural beryl (Be3Al2Si6O18) as a model system, we present a quantitative analysis of atomic occupancy within its channels. Through high-angle annular dark-field (HAADF) imaging, we clearly demonstrate the presence of Cs atoms within the channels. Furthermore, employing statistical analysis of atomic column intensities and comparison with a series of multislice simulations, we successfully determine the three-dimensional positions of individual Cs atoms within the channels. Thereby, we also reveal that the Cs atoms are non-uniformly distributed within the channels. By extracting the necessary information from a single high-resolution micrograph, we minimize the adverse effects of beam damage, making this methodology a promising approach for the analysis of diverse porous materials.