Carbonyls are among the most abundant volatile organic compounds in
the atmosphere, and their C=O chromophores allow them to photolyse.
However, carbonyl photolysis reactions
are not restricted to the excited state:
the C=O chromophore allows relaxation to, and reaction on, the ground
state, following photon absorption.
In this paper, the energetic thresholds for eight ground state reactions
across twenty representative carbonyl
species are calculated using double-hybrid density functional theory. Most
reactions are found to be energetically
accessible within the maximum photon energy available in the troposphere,
but are absent in contemporary atmospheric chemistry models.
Structure–activity relationships are
then elucidated so that the significance
of each reaction pathway for particular
carbonyl species can be predicted based
upon their class. The calculations here
demonstrate that ground state photolysis pathways are ubiquitous in carbonyls and should not be ignored in the
analysis of carbonyl photochemistry.
InstitutionThe University of Sydney
ORCID For Submitting Author0000-0001-6955-1167
Declaration of Conflict of InterestNone
Version NotesFirst versio, pre-print upload