2011 - Cooperative Institute for Research in Environmental Sciences ...

Veronica Vaida
Light- and Water-Mediated Chemistry
in the Earth’s Atmosphere
FUNDING: NATIONAL SCIENCE FOUNDATION,
CIRES INNOVATION RESEARCH PROGRAM
Our program, at the
interface of physical
chemistry and atmospheric
science, has originated
in the last decade
new ideas concerning
water- and sunlightmediated
processes in
planetary atmospheres,
including the contemporary
and prebiotic Earth.
My approach uses fundamental
chemical physics
to address complex
problems where atmospheric
measurements
and models disagree.
In response to observations
of high radical
concentrations with the
Sun near the horizon, our group, using red-light-initiated
photochemistry, pointed to the role of water in catalysis
and/or suppression of atmospheric reactions. This chemistry
resulted in mechanisms connecting volatile organic
compounds to aerosol nucleation.
Properties of atmospheric aerosols are highly nonlinear,
resulting in uncomfortably large uncertainties in aerosol
effects on climate. Inspired by atmospheric measurements,
which established that aerosols have a large organic content,
we proposed that a significant population of organic
aerosols consists of an aqueous core with an organic
surface film and pointed to the profound consequences
to their morphology and optical and chemical properties.
Our research group investigates the fundamental physical
chemistry of interfacial organic films and explores the
consequences of these results with theoretical models.
KAITO TAKAHASHI (SKODJE GROUP)
Figure 1: Lowering of the transition state energy by water in the hydration
of formaldehyde to methanediol.
JESSICA AXSON (VAIDA GROUP)
Figure 2: The water- and light-mediated chemistry of organic atmospheric
molecules affects their chemistry and aerosol nucleation.
CIRES Annual Report 2011 55