Open AccessCoupled infrared extinction and size distribution measurements for several clay components of mineral dust aerosol
Author(s) -
Hudson Paula K.,
Gibson Elizabeth R.,
Young Mark A.,
Kleiber Paul D.,
Grassian Vicki H.
Publication year - 2008
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2007jd008791
Subject(s) - kaolinite , extinction (optical mineralogy) , absorbance , aerosol , mie scattering , materials science , particle size , infrared , particle size distribution , mineralogy , molar absorptivity , analytical chemistry (journal) , particle (ecology) , montmorillonite , clay minerals , optics , chemistry , geology , physics , light scattering , scattering , composite material , environmental chemistry , oceanography , organic chemistry
Simultaneous size distributions and Fourier transform infrared extinction spectra have been measured for several clay components of mineral dust aerosol (illite, kaolinite, and montmorillonite) in the fine particle–sized mode (D = 0.1–1 μ m). Published optical constants have been used in combination with the measured size distributions in spectral simulations for comparison to the measured extinction spectrum. In general, the Mie theory simulation does not accurately reproduce the peak position or band shape for the prominent Si—O stretch resonance near 9.5 μ m (ca. 1050 cm −1 ) for any of the clays. The resonance peak in the Mie simulation is consistently blue shifted (27–44 cm −1 ) relative to the experimental spectrum. Additionally, the integrated absorbance in the resonance band is underpredicted for all three clay compounds. Spectral simulations based on various distributions of ellipsoid‐shaped particles better reproduce the experimental spectrum including the peak position, band shape, and integrated absorbance for these fine clay aerosols.