title: Fractal morphology of black carbon aerosol enhances absorption in the thermal infrared wavelengths.
abstract: In this Letter, we numerically calculate the mass absorption cross sections (MACs) of black carbon fractal aggregates in the thermal infrared solar spectrum. Compared to equivalent-size spheres, the MAC values of aggregates show a percent enhancement of ≈150 and 400 at small and large length scales, respectively. The absorption properties of aggregates with size parameters >1 surprisingly continued to remain in the Rayleigh optics regime. We explain this phenomenon using the Maxwell-Garnett effective medium theory and the concept of phase shift parameter.
authors.forename: William R
authors.initials: WR
authors.lastname: Heinson
authors.forename: Rajan K
authors.initials: RK
authors.lastname: Chakrabarty