title: Wavelength-dependent optical extinction of carbonaceous particles in atmospheric aerosols and interstellar dust.
abstract: Optical extinction spectra for particles of structurally disordered carbonaceous material (carbon black, soot) are discussed in terms of the effects of size and shape and the difference between coagulated and coalesced particles. For this purpose, the orientation-averaged specific extinction for several compact and open aggregates of spherical particles is calculated and compared with the specific extincton by homogeneous particles, i.e., volume-equivalent sphere and elongated spheroids. The extinction spectra are calculated for wavelengths from 0.2 to 1000 microm by use of the optical constants for the carbonaceous materials of Jäger et al. [Astron. Astrophys. 332, 291 (1998)] and Schnaiter et al. [Astrophys. J. 498, 486 (1998)]. Comparisons with the model case of particles composed of graphite and with measurements of diesel soot aerosols are made.
authors.affiliation: Institute for Physics A, Rheinisch-Westfälische Technische Hochschule Aachen, 52056 Aachen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Quinten
authors.forename: Uwe
authors.initials: U
authors.lastname: Kreibig
authors.forename: Thomas
authors.initials: T
authors.lastname: Henning
authors.forename: Harald
authors.initials: H
authors.lastname: Mutschke