Monochromated electron energy-loss spectroscopy (EELS) is employed to determine the optical properties of carbonaceous aerosols from the infrared to the ultraviolet region of the spectrum. It is essential to determine their optical properties to understand their accurate contribution to radiative forcing for climate change. The influence of surface and interface plasmon effects on the accuracy of dielectric data determined from EELS is discussed. Our measurements show that the standard thin film formulation of Kramers−Kronig analysis can be employed to make accurate determination of the dielectric function for carbonaceous particles down to about 40 nm in size. The complex refractive indices of graphitic and amorphous carbon spherules found in the atmosphere were determined over the wavelength range 200–1,200 nm. The graphitic carbon was strongly absorbing black carbon, whereas the amorphous carbon shows a more weakly absorbing brown carbon profile. The EELS approach provides an important tool for exploring the variation in optical properties of atmospheric carbon.

Carbon nanotubes (CNTs) are successfully immobilized on a bamboo charcoal by chemical vapor deposition of gaseous tetraethyl orthosilicate (TEOS). Electron microscopies, Raman spectroscopy and electron energy loss spectroscopy are used to characterize the sample. The CNTs found on the bamboo charcoal support were several microns long, and their diameters ranged from 50nm to 300nm. From the high resolution transmission electron microscopic analysis, we found that the CNTs were composed of ∼30 layers of graphitic carbon sheets. Amorphous droplets were also found at the tips of the CNTs. This suggested that the growth of the CNT was via a vapor-liquid-solid mechanism. The amorphous droplets contained calcium, silicon and oxygen. The calcium impurity was originated from the bamboo while the silicon impurity was supplied by the TEOS. CNTs partially filled with calcium silicate were also found. It was evident that calcium silicate had played a critical role in the formation of these CNTs.