- Raman Spectroscopy of Single Particles Levitated by an Electrodynamic Balance for Atmospheric Studies

2010 ◽  
pp. 174-211 ◽  
Keyword(s):  
Raman Spectroscopy ◽  
Single Particles ◽  
Electrodynamic Balance

Sol-gel processing of nanocrystalline haematite thin films

1997 ◽  
Vol 12 (6) ◽  
pp. 1441-1444 ◽  
Author(s):  
L. Armelao ◽  
A. Armigliato ◽  
R. Bozio ◽  
P. Colombo
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Single Particles ◽  
X Ray ◽  
Transmission Electron ◽  
Gel Processing

The microstructure of Fe2O3 sol-gel thin films, obtained from Fe(OCH2CH3)3, was investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy. Samples were nanocrystalline from 400 °C to 1000 °C, and the crystallized phase was haematite. In the coatings, the α–Fe2O3 clusters were dispersed as single particles in a network of amorphous ferric oxide.

Effect of ammonium salts on the photochemical degradation of iron containing organic aerosol

2020 ◽  
Author(s):  
Ulrich Krieger ◽  
Nir Bluvshtein ◽  
Jing Dou
Keyword(s):  
Citric Acid ◽  
Gas Phase ◽  
Degradation Rate ◽  
Uv Light ◽  
Lower Troposphere ◽  
Organic Aerosol ◽  
Photochemical Degradation ◽  
Single Particles ◽  
Electrodynamic Balance ◽  
Humidity Dependence

<p>Formation of organic aerosol by oxidation of gas phase compounds has been intensely studied, and is much better understood than the aerosol ageing transformations during the lifetime of organic aerosol. Aerosol ageing influences how those aerosol particles affect climate and human health and is still not well constrained in current models.</p><p>Photochemistry in the condensed phase is an important mechanism responsible for ageing of organic aerosol. In the lower troposphere, where UV light intensity with sufficiently low wavelength to directly photolyze aerosol components is low, indirect photochemistry (catalyzing redox processes of non-absorbing molecules) is especially relevant. Recently we studied transition metal complex photochemistry in single particles levitated in an electrodynamic balance. In particular, we investigated the aqueous iron(III)-citrate/citric acid system and found that irradiation at 473 nm led to rapid and significant degradation of the citric acid. Up to 80% of the initial particle mass was partitioned to the gas phase with the degradation rate depending on kinetic transport limitations of oxygen. These kinetic limitations arise are influenced strongly by the relative humidity dependence of particle viscosity where water acts as a plasticizer.</p><p>Here we will report on photochemical degradation experiments adding various salts in different (ammonium sulfate, ammonium bisulfate, etc.) to the reference system iron(III)-citrate/citric acid. Preliminary experiments suggest that pH of the aerosol particle influences the degradation rate in this system significantly.</p>

Raman Investigation of Photopolymerization Reactions of Single Optically Levitated Microparticles

1996 ◽  
Vol 50 (7) ◽  
pp. 823-828 ◽  
Author(s):  
C. Esen ◽  
T. Kaiser ◽  
G. Schweiger
Keyword(s):  
Raman Spectroscopy ◽  
Raman Spectrum ◽  
Raman Scattering ◽  
Polymerization Reaction ◽  
Single Particles ◽  
On Line ◽  
Optical Levitation ◽  
Monomer Droplet ◽  
Arc Excitation

Raman spectroscopy was used to investigate polymerization reactions in a single micrometer-sized monomer droplet. An Ar+ laser levitated the microparticles and simultaneously excited the Raman scattering. The polymerization reaction was initiated by exposing the monomer droplets to the UV radiation of a mercury arc excitation lamp. The Raman spectrum of the reacting particle was investigated on-line. The results demonstrate that the combination of the technique of optical levitation and Raman spectroscopy allows nondestructive in situ measurements of single particles and is therefore very useful for the study of fundamental processes.

Water diffusion measurements of single charged aerosols using H2O/D2O isotope exchange and Raman spectroscopy in an electrodynamic balance

2019 ◽  
Vol 21 (27) ◽  
pp. 15062-15071 ◽  
Author(s):  
Katherine A. Nadler ◽  
Pyeongeun Kim ◽  
Dao-Ling Huang ◽  
Wei Xiong ◽  
Robert E. Continetti
Keyword(s):  
Raman Spectroscopy ◽  
Isotope Exchange ◽  
Water Diffusion ◽  
Electrodynamic Balance ◽  
Charged Aerosols

We report water diffusion measurements on single charged aerosols using isotope exchange in an electrodynamic balance.

Study of the Phase Transformation of Single Particles of Ga2O3by UV-Raman Spectroscopy and High-Resolution TEM

2013 ◽  
Vol 8 (9) ◽  
pp. 2189-2195 ◽  
Author(s):  
Xiang Wang ◽  
Qian Xu ◽  
Fengtao Fan ◽  
Xiuli Wang ◽  
Mingrun Li ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Phase Transformation ◽  
High Resolution ◽  
Single Particles ◽  
Uv Raman Spectroscopy ◽  
High Resolution Tem ◽  
Uv Raman

Near-infrared Raman spectroscopy of single particles

2001 ◽  
Vol 20 (5) ◽  
pp. 255-262 ◽  
Author(s):  
Katsuhiro Ajito ◽  
Keiichi Torimitsu
Keyword(s):  
Raman Spectroscopy ◽  
Near Infrared ◽  
Single Particles

scholarly journals Diffusivity measurements of volatile organics in levitated viscous aerosol particles

2017 ◽  
Author(s):  
Sandra Bastelberger ◽  
Ulrich K. Krieger ◽  
Beiping Luo ◽  
Thomas Peter
Keyword(s):  
Atmospheric Chemistry ◽  
Glassy State ◽  
Field Measurements ◽  
Tetraethylene Glycol ◽  
Resonance Spectroscopy ◽  
Hygroscopic Growth ◽  
Single Particles ◽  
Diffusion Limitations ◽  
Electrodynamic Balance ◽  
Evaporative Loss

Abstract. Field measurements indicating that atmospheric secondary aerosol (SOA) particles can be present in a highly viscous, glassy state have spurred numerous studies addressing low diffusivities of water in glassy aerosols. The focus of these studies is on kinetic limitations of hygroscopic growth and the plasticizing effect of water. In contrast, much less is known about diffusion limitations of organic molecules and oxidants in viscous matrices. These may affect atmospheric chemistry and gas-particle partitioning of complex mixtures with constituents of different volatility. In this study, we quantify the diffusivity of a volatile organic in a viscous matrix. Evaporation of single particles generated from an aqueous solution of sucrose and small amounts of volatile tetraethylene glycol (PEG-4) is investigated in an electrodynamic balance at controlled humidity (RH) and temperature. The evaporative loss of PEG-4 as determined by Mie resonance spectroscopy is used in conjunction with a radially resolved diffusion model to retrieve translational diffusion coefficients of PEG-4. Comparison of the experimentally derived diffusivities with viscosity estimates for the ternary system reveals a breakdown of the Stokes-Einstein relationship, which has often been invoked to infer diffusivity from viscosity. The evaporation of PEG-4 shows pronounced RH and temperature dependencies and is severely depressed for RH ≲ 30 %, corresponding to diffusivities

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