Variation of Single Particle Mid-Infrared Emission Spectrum with Particle Size

Hunt, Graham R.; Logan, Lloyd M.

doi:10.1364/ao.11.000142

Cited by 102 publications

(77 citation statements)

References 10 publications

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“…Two blackbody targets (at ȁ70Њ and the sample also has an emissivity of unity. Commonly, 100ЊC) were measured to determine the instrument re-however, geologic materials have a maximum emissivity sponse function and instrument temperature used for data that ranges between 0.98 and 1.0 (Salisbury et al 1991 as calibration. The emissivity spectra of the minerals were discussed in Ruff et al 1997).…”

Section: Introductionmentioning

confidence: 99%

“…Within this area of transparency the emissivity spectra change shape. Previous studies (e.g., are distinct high-emissivity features at ȁ1800 and 1960 Lyon 1964, Aronson et al 1966, cm Ϫ1 that result from combination or over tones of the Vincent and Hunt 1968, Conel 1969, Hunt and Logan 1972 Wald andSalisbury 1995, Mustard andHays 1997) into the effective particle size of the sample in addition have addressed the issue of energy scattering and the effect to composition. of particle size on midinfrared spectra.…”

mentioning

confidence: 99%

“…Precision analysis of the 3 band showed that Logan standard deviation of the 3 band emissivity was ϭ 0.0045. 1972, Salisbury et al 1991, Salisbury andWald 1992). Figure 3a presents the calcite particle-size spectra.…”

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confidence: 99%

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Thermal Infrared Emission Spectroscopy of Salt Minerals Predicted for Mars

Lane

Christensen

1998

Icarus

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Section: Introductionmentioning

confidence: 99%

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confidence: 99%

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Thermal Infrared Emission Spectroscopy of Salt Minerals Predicted for Mars

Lane

Christensen

1998

Icarus

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“…There exists convincing experimental evidence that characteristic spectral structures which show up in the IR reflection or transmission spectra of a crystalline material, depend on whether the studied sample appears in bulk or particulate form (Conel 1969;Hunt & Logan 1972;Huffman 1977). Indeed, in addition to the frequency dependent complex refractive index proper for the bulk stuff, also the size and shape of the grains can be singled out among the factors which affect the aspect of a particulate spectrum (Hunt & Logan 1972).…”

Section: Bulk Optical Constants Versus Particulate Optical Constantsmentioning

confidence: 99%

“…Indeed, in addition to the frequency dependent complex refractive index proper for the bulk stuff, also the size and shape of the grains can be singled out among the factors which affect the aspect of a particulate spectrum (Hunt & Logan 1972). The bulk refractive index is well defined in the realm of electromagnetic waves described by Maxwell equations, and in principle can be easily related to the optical properties, e.g., of a large crystalline slab.…”

Section: Bulk Optical Constants Versus Particulate Optical Constantsmentioning

confidence: 99%

Optical constants of powdered limestone obtained by taking into account the grain shapes: Applicability to Martian studies

Jurewicz¹,

Orofino²,

Marra³

et al. 2003

A&A

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Abstract. The modelling and the interpretation of infrared spectra exhibited by astronomical dusty objects require fair acquaintance with complex refractive indices, the so-called "optical constants", of cosmic analog materials. It turns out that the spectra of the latter, in case of a crystalline granular material, depend on the size and the shape of the grains and may differ from the spectra of the same material but in bulk form. This phenomenon can be very elegantly accounted for by considering optical lattice excitations specific to small particles, the so-called "surface modes". We present a study of the spectral behaviour, in the 1.5-62.5 µm range, of the optical constants of a particulate sample of limestone, a typical carbonate material mainly composed of calcite (CaCO 3 ). Shape effects have been accounted for by considering a collection of randomly oriented ellipsoids with various continuous distributions of shape parameters. It is shown that in the spectral region around the bands at 32 µm and 44 µm, whose assignment to surface modes raises no doubt, the optical constants derived for various shape distributions are markedly different from each other. We find that the best agreement between laboratory and theoretical spectra is obtained for spheres while for two continuous distributions of ellipsoids the fits are slightly worse. In other words the optical constants, that describe best the interaction between electromagnetic radiation and our limestone sample, are those derived by using Mie theory (valid for spheres); this is in agreement with SEM analysis which indicates a spheroidal shape of the particles. Such conclusions, valid for limestone particles, cannot be extrapolated directly to other particles and/or materials, since every case has to be treated independently. They should nevertheless be helpful in avoiding the possible error of interpreting absorption spectra of particulate crystalline stuffs without taking into account the effects of particle size and shape.

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Quantitative compositional analysis of sedimentary materials using thermal emission spectroscopy: 1. Application to sedimentary rocks

Thorpe

Rogers

Bristow

et al. 2015

J. Geophys. Res. Planets

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Thermal emission spectroscopy is used to determine the mineralogy of sandstone and mudstone rocks as part of an investigation of linear spectral mixing between sedimentary constituent phases. With widespread occurrences of sedimentary rocks on the surface of Mars, critical examination of the accuracy associated with quantitative models of mineral abundances derived from thermal emission spectra of sedimentary materials is necessary. Although thermal emission spectroscopy has been previously proven to be a viable technique to obtain quantitative mineralogy from igneous and metamorphic materials, sedimentary rocks, with natural variation of composition, compaction, and grain size, have yet to be examined. In this work, we present an analysis of the thermal emission spectral (~270–1650 cm−1) characteristics of a suite of 13 sandstones and 14 mudstones. X‐ray diffraction and traditional point counting procedures were all evaluated in comparison with thermal emission spectroscopy. Results from this work are consistent with previous thermal emission spectroscopy studies and indicate that bulk rock mineral abundances can be estimated within 11.2% for detrital grains (i.e., quartz and feldspars) and 14.8% for all other mineral phases present in both sandstones and mudstones, in comparison to common in situ techniques used for determining bulk rock composition. Clay‐sized to fine silt‐sized grained phase identification is less accurate, with differences from the known ranging from ~5 to 24% on average. Nevertheless, linear least squares modeling of thermal emission spectra is an advantageous technique for determining abundances of detrital grains and sedimentary matrix and for providing a rapid classification of clastic rocks.

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Variation of Single Particle Mid-Infrared Emission Spectrum with Particle Size

Cited by 102 publications

References 10 publications

Thermal Infrared Emission Spectroscopy of Salt Minerals Predicted for Mars

Thermal Infrared Emission Spectroscopy of Salt Minerals Predicted for Mars

Optical constants of powdered limestone obtained by taking into account the grain shapes: Applicability to Martian studies

Quantitative compositional analysis of sedimentary materials using thermal emission spectroscopy: 1. Application to sedimentary rocks

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