Delocalisation in images of Pt nanoparticles

Delocalisation is an imaging artefact that results in the presence of lattice fringes outside a crystal imaged in a transmission electron microscope (TEM) in the presence of spherical aberration and/ or defocus. Here, we show that delocalisation can be used to determine the absolute defocus values of chosen features in a specimen from a defocus series of images, what may be used to improve computer reconstruction methods. These values are important for optimising the accuracy of information about the specimen obtained using techniques such as exit wavefunction restoration