ABSTRACT
Progress in the synthesis of nanoscale objects has led to the appearance of scale-related properties not seen or di erent from those found in microscopic/macroscopic systems. For instance, monolayer-protected Au nanoparticles with average diameter of 1.9 nm have been reported to show ferromagnetism while bulk Au is diamagnetic (Hasegawa 2007). Nanotechnology brings the opportunity of tailoring systems to speci c needs, signi - cantly modifying the physicochemical properties of a material by controlling its size at the nanoscale. Size e ects can be of different types. Smooth size e ects can be described in terms of a size parameter such that we recover the bulk behavior when this parameter is large. e physicochemical properties then follow relatively simple scaling laws, such as a power-law dependence, that yield a monotonous variation with size. Speci c size e ects, on the contrary, are not amenable to size scaling because the variation of the relevant property with the size is irregular or nonmonotonic. ey are characteristic of small clusters. Finally, some properties are unique for nite systems and do not have an analog in the behavior of the corresponding bulk matter (Jortner and Rao 2002, Berry 2007).
