Refractive-index measurements of single micron-sized carbon particles

Pluchino, Antonino B.; Goldberg, S. S.; Dowling, Jerome M.; Randall, C. M.

doi:10.1364/ao.19.003370

Cited by 83 publications

(24 citation statements)

References 11 publications

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“…Cooke and Kerker (1973) used a Differential 11 for comparing PSL light scattering with Mie theory, and Davis and Chorbajian (1974) adapted the instrument to measure the evaporation rates of single D O P droplets. Additional light scattering studies were reported by McRae (1982), who determined the refractive index of cigarette smoke droplets, by olland (1982), who also used the ential I1 for measuring the refractive index and size of PSL particles, and by Pluchino et al (1980). The latter investigators determined the complex refractive index of micron-sized carbon electrostatic balance they built…”

Section: Odsmentioning

confidence: 98%

Transport Phenomena with Single Aerosol Particles

Davis¹

1982

Aerosol Science and Technology

138

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Section: Odsmentioning

confidence: 98%

Transport Phenomena with Single Aerosol Particles

Davis¹

1982

Aerosol Science and Technology

138

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“…Mie scattering is of particular importance in this study. It applies to the particular case of light scattering by an absorbing spherical object 20,27 . The Mie theory turned out to be extremely successful to precisely describe cloud or dust light transmission in metrology and aeronomy, but also in many other areas of research such as astronomy and chemistry for modelling the interaction of starlight with interstellar dust, or to estimate the size of particles in colloidal suspensions.…”

Section: Ii1 Absorption and Scatteringmentioning

confidence: 99%

Minimising contributions from scattering in infrared spectra by means of an integrating sphere

Dazzi

Deniset‐Besseau

Lasch

2013

Analyst

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Mid-infrared spectra of biological matter such as tissues, or microbial and eukaryotic cells measured in a transmission-type optical setup frequently show strongly distorted line shapes which arise from mixing of absorption and scattering contributions. Scattering-associated distorted line shapes may considerably complicate the analysis and interpretation of the infrared spectra and large efforts have been made to understand the mechanisms of scattering in biological matter and to compensate for spectral alterations caused by scattering. The goals of the present study were twofold: Firstly, to get a deeper understanding of the physics of scattering of biological systems and to explore how physical parameters of the scatterers such as shape, size and refractive index influence the line shape distortions observed. In this context, simulations based on the full Mie scattering formalism for spherical particles were found to be useful to explain the characteristics of the Mie scatter-associated distortions and yielded a size criterion for the scattering particles similar to the well-known near field criterion. The second objective of the study was to investigate whether alternative optical setups allow to minimise the effects of scattering. For this purpose, an optical system is proposed which is composed of an integrating sphere unit originally designed for diffuse reflection measurements, an off-axis DLaTGS detector to collect scattered and transmitted light components and a commercial Fourier transform infrared (FTIR) spectrometer. In the context of this study transmission type (tt-) FTIR spectra and spectra acquired by means of the integrating sphere setup (is-FTIR) were acquired from monodisperse poly(methyl) methacrylate (PMMA) microspheres of systematically varying size. The tt-FTIR spectral data of different PMMA particles confirmed earlier observations such as the presence of size-dependent oscillating spectral baselines, peaks shifts, or derivative-like spectral line shapes. Such effects could be dramatically minimised when is-FTIR spectra were acquired by the integrating sphere unit. Utilisation of an integrating sphere is suggested as a convenient and easy-to use alternative to computer-based methods of scatter correction.

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“…49,50 In the case of graphite, 51 k shows a broad resonance peak at about 260 nm (∼4.8 eV). Moreover, the value of k at vis wavelengths is about 1.4 for graphite (i.e., about twice the value of soot at the same wavelengths).…”

Section: Ethylene Soot Versus Other Carbonaceous Samplesmentioning

confidence: 99%

Comparative NEXAFS Study on Soot Obtained from an Ethylene/Air Flame, a Diesel Engine, and Graphite

Stasio

Braun

2005

Energy Fuels

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Microstructure and molecular structure properties of different carbonaceous byproducts from combustion are fundamental to evaluate the radiative properties of such materials when combustion aerosols interact with solar radiation in atmosphere. Carbon near edge X-ray absorption fine structure (NEXAFS) spectroscopy is presented as an analytical technique for the carbon-specific characterization of various soot species. Ethylene soot, diesel soot, and carbon black NEXAFS spectra are discussed in relation to graphite as the most genuine model compounds of soot. Characteristic resonances in the spectra allow for the direct molecular speciation of the graphite-like solid core in soot, surface functional groups, and aromatic and aliphatic components, depending on the origin of the soot. Moreover, in the experimental case of ethylene soot samples probed at increasing distances from the burner nozzle, namely, at increasing residence times, NEXAFS experiments lead to the evidence that the soot collected near the nozzle appears to be more graphitized than soot sampled at larger heights-above-burner, in qualitative agreement with laser light scattering depolarization measurements reported here and previous findings obtained by electron microscopy characterization. The possible implications of the presented results on soot formation mechanism, combustion source attribution of carbon particulates, and UV-vis sunlight absorption by black carbon aerosols are briefly discussed.

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Refractive-index measurements of single micron-sized carbon particles

Abstract: The differential scattering cross section for single carbon particles is measured in the visible. The data are mathematically inverted to obtain the complex index of refraction and particle radius.

Cited by 83 publications

References 11 publications

Transport Phenomena with Single Aerosol Particles

Transport Phenomena with Single Aerosol Particles

Minimising contributions from scattering in infrared spectra by means of an integrating sphere

Comparative NEXAFS Study on Soot Obtained from an Ethylene/Air Flame, a Diesel Engine, and Graphite

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