Defects and their associated long-range strain fields are of considerable importance in many areas of materials science. For example, a major challenge facing the semiconductor industry is to understand the influence of defects on device operation, a task made difficult by the fact that their interactions with charge carriers can occur far from defect cores, where the influence of the defect is subtle and difficult to quantify. The accurate measurement of strain around defects would therefore allow more detailed understanding of how strain fields affect small structures-in particular their electronic, mechanical and chemical properties--and how such fields are modified when confined to nanometre-sized volumes. Here we report the measurement of displacements around an edge dislocation in silicon using a combination of high-resolution electron microscopy and image analysis inherited from optical interferometry. The agreement of our observations with anisotropic elastic theory calculations is better than 0.03 A. Indeed, the results can be considered as an experimental verification of anisotropic theory at the near-atomic scale. With the development of nanostructured materials and devices, we expect the use of electron microscopy as a metrological tool for strain analysis to become of increasing importance.

in particular the leached layer theory. Most importantly, our data provide critical evidence for 51 a single mechanism based on interfacial dissolution-reprecipitation. This concept not only 52 unifies weathering processes for the first time, but we also suggest that nanoscale-surface 53 processes can have a potentially negative impact on CO 2 uptake associated with chemical 54 weathering. The results in this study, when combined with recently published research on 55 fluid-assisted mineral replacement reactions, supports the idea that dissolution-reprecipitation 56 is a universal mechanism controlling fluid-mineral interactions . 57Based on this we propose the existence of a chemical weathering continuum based solely on 58 the interfacial dissolution-reprecipitation mechanism. 59 3

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