A density function theory study on the properties and decomposition of CF 3 OF Hong-Ming Yin * , Ju-Long Sun, Ya-Min Li, Guo-Zhong He, Ke-Li Han State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, 116023 Dalian, China Received 10 August 2001; in final form 11 March 2002 Abstract ThedensityfunctiontheorywasusedtocalculatethepotentialenergysurfaceforthedecompositionofCF 3 OF.The geometries, vibrational frequencies and energies of all stationary points were obtained. The calculated harmonic fre- quenciesagreedwellwiththeexperimentalones.ThreedecompositionchannelsofCF 3 OFwerestudied.Thecalculated reaction enthalpy (29.85 kcal/mol) of the elimination reaction CF 3 OF ! CF 2 O þ F 2 was in good agreement with the experimental value (27.7 kcal/mol). The O–F bond of CF 3 OF is broken easily by comparing the energies, while the decomposition channel to yield the CF 3 O and F radicals is the main reaction path. Ó 2002 Published by Elsevier Science B.V. 1. Introduction The pyrolysis and photolysis of trifluoromethyl hypofluorite (CF 3 OF)havebeenthefocusofmany investigations, because it is a convenient source for thetrifluoromethoxyradicalwhichisveryimportant in combustion and atmospheric chemistry. This CF 3 Oradicalhasbeensuggestedtobeanimportant constituent in molecules containing the CF 3 O group, which may represent a special case of fluo- rine-catalyzedozoneloss[1].Meanwhile,theCF 3 O radicalmayalsoreactwithmanyatmosphericcon- taminants, such as NO [2–5], hydrocarbons [6–9], etc. Since the trifluoromethyl hypofluorite (CF 3 OF) molecule is a stable one, it can pass through a copper tube held at about 450 °C without being decomposed [10]. There are mainly three different channels in the decomposition of CF 3 OF, namely: CF 3 OF ! CF 3 O þ F ð1Þ CF 3 OF ! CF 3 þ OF ð2Þ CF 3 OF ! CF 2 O þ F 2 ð3Þ Saathoff and Zellner [8] reported that CF 3 O was generated directly by laser photolysis of CF 3 OF within a very short time. Porter and Cady [11] estimated channel (3) by thermal dissociation and electrical discharge. However, the decompo- sition mechanism of CF 3 OF has to be confirmed further. 26 April 2002 Chemical Physics Letters 356 (2002) 601–606 www.elsevier.com/locate/cplett * Corresponding author. Fax: +411-467-5584. E-mail address: hmyin@ms.dicp.ac.cn (H.-M. Yin). 0009-2614/02/$ - see front matter Ó 2002 Published by Elsevier Science B.V. PII:S0009-2614(02)00433-5