![]() A possible way out of this difficulty requires controlling the chirality directly in the synthesis process. Thus one can collect nanotubes with desired properties only on a small scale and at a high cost. Defect-free SWNTs are typically extracted from synthesis products that contain a mixture of defective and non defective nanotubes 9, 10, 11, 12. So far this expectation has not been fulfilled, mainly because it has not been possible to access large yields of single-walled nanotubes (SWNT) with a well-defined chirality 2, 3, 4, 5, 6, 7, which is the key factor governing their electronic properties 8. ![]() ![]() Since their discovery in 1991 1 carbon nanotubes have attracted great attention due to the expectation that they could lead to electronic devices with unprecedented capabilities. Direct observation of nanoparticles in the early stages of growth with unobtrusive laser probes should give insight on the particle formation mechanisms and may lead to better-controlled synthesis protocols. Observable spectral features include characteristic resonant behaviour, shape-dependent depolarization ratio, and mass-dependent line shape. Larger asymmetric nanoparticles would yield brighter signals, making possible to follow the evolution of the growing nanoparticle population from the evolution of the scattered intensity. ![]() We find that the resolution of the Rayleigh scattering probe is adequate to detect nanoparticles as small as C 60 at the expected concentrations of synthesis conditions in the arc periphery. We compute the Rayleigh scattering cross sections of the nanoparticles by combining light scattering theory for gas-particle mixtures with calculations of the dynamic electronic polarizability of the nanoparticles. We report a theoretical analysis showing that Rayleigh scattering could be used to monitor the growth of nanoparticles under arc discharge conditions. ![]()
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