Vibrational exciton coupling as a probe for phase transitions and shape changes of fluoroform aerosol particles
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Date
2009-01-07Type
- Journal Article
ETH Bibliography
no
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Abstract
Phase transitions and shape changes of aerosol particles play a fundamental role in atmospheric as well as technical processes involving aerosols. For the example of fluoroform particles, we demonstrate how information about both processes can be extracted from time-dependent infrared spectra by comparison with vibrational exciton calculations. We find volume crystallization rate constants for fluoroform particles in the range of Jv = 108–1010 cm−3 s−1 at a temperature of T = 78 K. Furthermore, our investigation reveals that supercooled fluoroform droplets crystallize to the most stable monoclinic bulk crystal structure. Immediately after crystallization, the particles have a cube-like shape which evolves with increasing time to an elongated shape. The present results provide new data for a better understanding of the Rapid Expansion of Supercritical Solutions when fluoroform is used as a supercritical solvent under expansion conditions which lead to fluoroform aerosol formation. Show more
Publication status
publishedExternal links
Journal / series
Physical Chemistry Chemical PhysicsVolume
Pages / Article No.
Publisher
Royal Society of ChemistryOrganisational unit
03961 - Signorell, Ruth / Signorell, Ruth
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ETH Bibliography
no
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