Related Experiment Video
Updated: Jun 15, 2026

Characterization of Biological Absorption Spectra Spanning the Visible to the Short-Wave Infrared
Published on: January 10, 2025
Relation between absorption coefficient and imaginary index of atmospheric aerosol constituents
Abstract:
The absorption coefficient per unit mass alpha(cm(2)g(-l)) for aerosols in the wavelength range lambda = 1.06-10.6 microm is shown to be a sensitive function of particle size distribution and of both imaginary and real indexes of refraction. Hence the imaginary index of refraction cannot be accurately determined from absorption measurements on an aerosol sample as attempted by S. A. Schleusener et al., Appl. Opt. 15, 2546 (1976), unless the size distribution and real index of the aerosol material are known. Similar difficulties arise in attempts to infer imaginary index from transmission measurements through aerosol samples as done by F. E. Volz, Appl. Opt. 11, 755 (1972); 12, 564 (1973) and K. Fischer, Beitr. Phys. Atmos. 43, 244 (1970). In addition, scattering losses can further complicate the determination of imaginary index from transmission measurements.
Related Concept Videos
UV–Vis Spectroscopy: Beer–Lambert Law
IR Spectrum
Transmittance is defined as the ratio of the radiant power passing through a sample to that from the radiation's source. Multiplying the transmittance by 100 gives the percent transmittance (%T), which varies between 100% (no absorption) and 0% (complete...
Adsorption Isotherms I
Infrared (IR) Spectroscopy: Overview
Different compounds display unique properties due to their...
IR Spectrum Peak Intensity: Amount of IR-Active Bonds
Thermodynamics: Activity Coefficient
The activity coefficient is a measure of the deviation from ideal behavior. When the ionic strength of the solution is minimal, the activity coefficient of an ionic species is close to unity, making...

