| Metal nanocrystals have been extensively studied for many years because of their applications in catalysis,optics,electronics,biological and chemical sensing and so on. Much progress has been made in size and shape-controlled synthesis of nanocrystals. Probably because of the quantum size effect,the literature work on measuring the concentration of nanocrystals are very little especially for that smaller than 10nm. However,the concentration of nanocrystals is a crucial parameter to explore the mechanism of size and shape control,and their effect on biological system.Furthermore, the measurement of the concentration is also important for the application of nanocrystals.In this thesis,the extinction,absorption and scattering spectra are calculated according to Mie theory and quantum correction.The unit volume extinction Qv-ext factor is proposed to study the relationship between the concentration and the optical properties of Pd nanocrystals.It is found that the influence of size,shape on the Uv-Vis spectra is little under the studied conditions while the imaginary part and the real part ofεm,,can affect the slope and intercept of log Qv-ext -logλplots,respectively.In the presence of PVP,Pd nanoparticles(1nm3)2Cl2 solution.The logA-logλplots of Pd nanocrystals with different concentration show the similar slopes.This observation supports that the influence of size on Qv-ext are little,which suggest that the concentration of Pd nanoctystal can be achieved under the synthesis condition.
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