Quantitative diffuse reflectance and transmittance spectroscopy of loosely packed powders

A self-consistent discontinuum theory describing the dependence of the diffuse reflectance and diffuse transmittance of powders on their optical absorption coeff. is presented. The theory is valid for particle sizes large compared to the exciting wavelength. It constitutes generalization and evolution of the statistical theory of abs. diffuse reflectance of powders put forth by N. T. Melamed (1963). Exptl. evidence of the spectroscopic use of the theory in detg. abs. optical absorption coeffs. self-consistently from both the reflectance and transmittance measurement channels sequentially is provided for 2 powders, and the new photothermal technique of Diffuse Transmittance IR Fourier Transform Spectroscopy (DTIFTS) is introduced. The transmittance channel can be used advantageously to measure small changes in optical absorption spectra, as it is more sensitive to such changes than the diffuse reflectance. Practical exptl. limits of the validity of the discontinuum theory are also established.


Published in:
Spectrochimica Acta Part A: Molecular Spectroscopy, 47, 7, 943-971
Year:
1991
Keywords:
Note:
Copyright 2003 ACS
CAPLUS
AN 1991:569382
CAN 115:169382
73-3
Optical, Electron, and Mass Spectroscopy and Other Related Properties
Lab. Chim. Tech.,Ec. Polytech. Fed. Lausanne,Lausanne,Switz. FIELD URL:
Journal
SAMCAS
written in English.
Optical absorption; Optical reflection (by loosely packed powders); Powders (diffuse reflectance and transmittance spectroscopy of loosely packed); Infrared spectrometry (Fourier-transform, diffuse transmittance, of powders)
Laboratories:




 Record created 2011-02-01, last modified 2018-09-13


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