title: Tropospheric photolysis rates of the acetaldehyde isotopologues CD₃CHO and CD₃CDO relative to CH₃CHO measured at the European Photoreactor Facility.
abstract: Acetaldehyde is a hazardous pollutant found in indoor and ambient air. Acetaldehyde photolysis is pressure- and wavelength-dependent with three distinct product channels. In this study, the photolysis rates of CH3CHO, CD3CDO, and CD3CHO are studied in natural tropospheric conditions using long path FTIR spectroscopy, at the European Photoreactor Facility (EUPHORE) in Valencia, Spain. The average relative photolysis rate as an average of four experiments for the fully deuterated isotopologue is j(CH3CHO)/j(CD3CDO) = 1.75 ± 0.04, and as a result of a single experiment j(CH3CHO)/j(CD3CHO) = 1.10 ± 0.10. These results, combined with our previous determination of j(CH3CHO)/j(CH3CDO) = 1.26 ± 0.03, provide mechanistic insight into the photodissociation dynamics of the photoexcited species. Despite the extensive isotopic scrambling in photoexcited acetaldehyde that has recently been reported, the position of the substitution has a clear effect on the relative photolysis rates.
authors: †Division of Combustion Physics, Department of Physics, Lund University, Professorsgatan 1, SE-22363 Lund, Sweden.
authors: Elna J K
authors: EJ
authors: Nilsson
authors: ‡Copenhagen Center for Atmospheric Research, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen OE, Denmark.
authors: Jimmy
authors: J
authors: Heimdal
authors: §Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, Pb. 1033 - Blindern, 0315 Oslo, Norway.
authors: Lihn
authors: L
authors: Bache-Andreassen
authors: ‡Copenhagen Center for Atmospheric Research, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen OE, Denmark.
authors: Matthew S
authors: MS
authors: Johnson
authors: §Centre for Theoretical and Computational Chemistry, Department of Chemistry, University of Oslo, Pb. 1033 - Blindern, 0315 Oslo, Norway.
authors: Claus J
authors: CJ
authors: Nielsen