Characterization of inorganic salt particles by Raman spectroscopy

Tang, I.N.; Fung, K. H.

doi:10.1016/0021-8502(89)90106-7

Cited by 46 publications

(24 citation statements)

References 21 publications

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“…The peaks were assigned to specific compounds and minerals by comparison with reported values from the literature (Tang and Fung, 1989;Ivleva et al, 2007;Freeman et al, 2008;Baustian et al, 2012;Laskina et al, 2013) and Raman databases. The peak positions were also verified by measuring standard pure chemical compounds using the current Raman system.…”

Section: Individual Particle Analysesmentioning

confidence: 99%

Characterization of individual ice residual particles by the single droplet freezing method: a case study in the Asian dust outflow region

Iwata

Matsuki

2018

Atmos. Chem. Phys.

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Abstract. In order to better characterize ice nucleating (IN) aerosol particles in the atmosphere, we investigated the chemical composition, mixing state, and morphology of atmospheric aerosols that nucleate ice under conditions relevant for mixed-phase clouds. Five standard mineral dust samples (quartz, K-feldspar, Na-feldspar, Arizona test dust, and Asian dust source particles) were compared with actual aerosol particles collected from the west coast of Japan (the city of Kanazawa) during Asian dust events in February and April 2016. Following droplet activation by particles deposited on a hydrophobic Si (silicon) wafer substrate under supersaturated air, individual IN particles were located using an optical microscope by gradually cooling the temperature to −30 • C. For the aerosol samples, both the IN active particles and non-active particles were analyzed individually by atomic force microscopy (AFM), micro-Raman spectroscopy, and scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDX). Heterogeneous ice nucleation in all standard mineral dust samples tested in this study was observed at consistently higher temperatures (e.g., −22.2 to −24.2 • C with K-feldspar) than the homogeneous freezing temperature (−36.5 • C). Meanwhile, most of the IN active atmospheric particles formed ice below −28 • C, i.e., at lower temperatures than the standard mineral dust samples of pure components. The most abundant IN active particles above −30 • C were predominantly irregular solid particles that showed clay mineral characteristics (or mixtures of several mineral components). Other than clay, Ca-rich particles internally mixed with other components, such as sulfate, were also regarded as IN active particle types. Moreover, sea salt particles were predominantly found in the non-active fraction, and internal mixing with sea salt clearly acted as a significant inhibiting agent for the ice nucleation activity of mineral dust particles. Also, relatively pure or fresh calcite, Ca(NO 3 ) 2 , and (NH 4 ) 2 SO 4 particles were more often found in the non-active fraction. In this study, we demonstrated the capability of the combined single droplet freezing method and thorough individual particle analysis to characterize the ice nucleation activity of atmospheric aerosols. We also found that dramatic changes in the particle mixing states during long-range transport had a complex effect on the ice nucleation activity of the host aerosol particles. A case study in the Asian dust outflow region highlighted the need to consider particle mixing states, which can dramatically influence ice nucleation activity.

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Section: Individual Particle Analysesmentioning

confidence: 99%

Characterization of individual ice residual particles by the single droplet freezing method: a case study in the Asian dust outflow region

Iwata

Matsuki

2018

Atmos. Chem. Phys.

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“…Since the coefficients aE and lE, am and 1M have the same denominators, both the internal and external fields will exhibit resonance when wo is coincident with a resonance frequency of the particle. In a similar fashion, the Raman field at frequency w outside the particle can also be written as (10) where the Raman outgoing field coefficients cE (l,m) and cM (l,m) are…”

Section: Inelastic Scattering Of Microspheresmentioning

confidence: 99%

Resonance structures in elastic and Raman scattering from microspheres

1991

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“…Previous studies of aerosols using Raman spectroscopy have focused on either single, levitated particles (Vehring et al 1998;Aardahl et al 1996;Buehler et al 1991;Tang and Fung 1989;Fung and Tang 1989) or streams of uniform, monodisperse particles (Schweiger 1987;Deverakonda et al 1998;Barnes et al 1997;Lermer et al 1997). These studies have elucidated many interesting and novel optical properties of these systems.…”

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confidence: 99%