Three-dimensional distribution of individual atoms in the channels of beryl

Nanoporous materials constitute a diverse group with numerous applications, including gas
storage and separation, catalysis, sensors, and electrochemical energy conversion and
storage [1]. Understanding the fundamental mechanisms of diffusion and adsorption of
atomic and molecular species within the pores of this class of materials is, therefore,
paramount. While the localization of single atoms in crystalline materials has been
demonstrated using high resolution TEM based techniques [2], the high susceptibility of most
nanoporous specimen to the electron beam presents significant challenges for quantitative
high-resolution investigations of these materials [3]. Here, we present our results on the
quantitative analysis of single atoms adsorbed within the channels of beryl (Be2AlSi6O18).
Through statistical analysis of the atomic column intensities and comparison with multiple
series of multislice simulations, we determine the local thickness of the specimen, as well as
the three-dimensional position of single adsorbed Cs atoms within the channels, based on a
single STEM high-angle annular dark-field (HAADF) image. Extracting all necessary
information from a single highresolution micrograph, enables us to minimize beam damage effects, offering a promising methodology also for the analysis of other porous
materials [4].