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Thermochromism of Model Organic Aerosol Matter

Rincón, Angela G. and Guzmán, Marcelo I. and Hoffmann, M. R. and Colussi, A. J. (2010) Thermochromism of Model Organic Aerosol Matter. Journal of Physical Chemistry Letters, 1 (1). pp. 368-373. ISSN 1948-7185.

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Laboratory experiments show that the optical absorptivity of model organic matter is not an intrinsic property, but a strong function of relative humidity, temperature, and insolation. Suites of representative polyfunctional C_(x)H_(y)O_(z) oligomers in water develop intense visible absorptions upon addition of inert electrolytes. The resulting mixtures reach mass absorption cross sections σ(532 nm) ~ 0.1 m^(2)/gC in a few hours, absorb up to 9 times more solar radiation than the starting material, can be half-bleached by noon sunlight in ~ 1 h, and can be repeatedly recycled without carbon loss. Visible absorptions red-shift and evolve increasingly faster in subsequent thermal aging cycles. Thermochromism and its strong direct dependences on ionic strength and temperature are ascribed to the dehydration of >CH−C(OH)< groups into >C═C< unsaturations by a polar E1 mechanism, and bleaching to photoinduced retrohydration. These transformations are deemed to underlie the daily cycles of aerosol absorption observed in the field, and may introduce a key feedback in the earth’s radiative balance.

Item Type:Article
Related URLs:
URLURL TypeDescription
Guzmán, Marcelo I.0000-0002-6730-7766
Hoffmann, M. R.0000-0001-6495-1946
Colussi, A. J.0000-0002-3400-4101
Additional Information:© 2010 American Chemical Society. Received Date: October 26, 2009; accepted Date: December 2, 2009; Published on Web Date: December 09, 2009. This project was financially supported by the National Science Foundation (ATM-0714329). A.G.R. acknowledges financial support from the Swiss National Science Foundation (PBL2-110274).
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Swiss National Science Foundation (SNSF)PBL2-110274
Issue or Number:1
Record Number:CaltechAUTHORS:20100526-092341428
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Official Citation:Thermochromism of Model Organic Aerosol Matter Angela G. Rincn, Marcelo I. Guzmn, M. R. Hoffmann, A. J. Colussi The Journal of Physical Chemistry Letters 2010 1 (1), 368-373
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:18450
Deposited By: Jason Perez
Deposited On:27 May 2010 18:20
Last Modified:09 Mar 2020 13:18

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