Gas phase UV absorption cross-sections for a series of amides A. Chakir a, * , G. Solignac b , A. Mellouki b , D. Daumont a a GSMA, UMR CNRS 6089, Departement de Chimie, Laboratoire de Chimie-Physique, Faculte ´ des Sciences, Universite ´ de Reims, Unite Mixte de Recherche 6089, Moulin de la housse, B.P. 1039, FR-51687 Reims Cedex 2, France b LCSR-CNRS, 1C avenue de la recherche scientifique 45071 Orle ´ans Cedex 02, France Received 23 November 2004; in final form 14 January 2005 Abstract The ultra violet absorption cross-sections of N,N-dimethyl formamide, N,N-dimethyl acetamide, N,N-dimethyl proprionamide, and 1-methyl-2-pyrrolidinone are reported. The measurements were carried out over the wavelength 210–270 nm in the temperature range 298–363 K using two different experimental systems (D 2 lamp – monochromator and D 2 lamp – diode array). This work pro- vides the first UV cross-section measurement for these amides. Ó 2005 Elsevier B.V. All rights reserved. 1. Introduction Amides constitute a large class of nitrogen contain- ing volatile organic compounds (NVOCs) that may be found as atmospheric contaminants. Number of amides are widely used as solvents or starting materi- als or intermediates in different industries (synthetic polymers, manufacture of dyes, synthesis of pesticides, preparation of medicine, etc.) [1–3], Amides are re- leased into the atmosphere following their use and also formed in situ as intermediate products in the degradation of amines [2–4]. Up to date, the atmo- spheric fate of amides in the gas phase is not well de- fined. Similarly to other volatile organic compounds (VOCs), they can undergo photolysis and chemical reaction with OH and NO 3 radicals and O 3 [5,6].A number of short chain amides have been subject to a limited kinetic studies with OH radicals which en- abled an estimation of their atmospheric lifetimes [7,8]. However, in order to provide a better knowledge of the atmospheric fate of amides, the contribution of the photolysis in their atmospheric removal has to be defined. This requires the knowledge of their UV–vis spectra, the photolysis rate and quantum yields. The present work reports the first UV–vis spectra in the gas phase for a series of amides: The experiments were conducted in two different lab- oratories using complementary techniques. 0009-2614/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.cplett.2005.01.060 * Corresponding author. Fax: +33 3 26 91 32 63. E-mail address: abdel.chakir@univ-reims.fr (A. Chakir). www.elsevier.com/locate/cplett Chemical Physics Letters 404 (2005) 74–78