Collect. Czech. Chem. Commun. 2003, 68, 2297-2308

The Importance of Photodissociative Trichloromethanol for Atmospheric Chemistry

Max Mühlhäusera,b,*, Melanie Schnella,c and Sigrid D. Peyerimhoffa

a Institut für Physikalische und Theoretische Chemie, Universität Bonn, Wegelerstrasse 12, 53115 Bonn, Germany
b Verfahrens- und Umwelttechnik (FH), Management Center Innsbruck, Egger-Lienz-Strasse 120, A-6020 Innsbruck, Austria
c Institut für Physikalische Chemie, Universität Hannover, Callinstrasse 3-3A, 30167 Hannover, Germany


Multireference configuration interaction calculations are carried out for ground and excited states of trichloromethanol to investigate two important photofragmentation processes relevant to atmospheric chemistry. For CCl3OH five low-lying excited states in the energy range between 6.1 and 7.1 eV are found to be highly repulsive for C-Cl elongation leading to Cl2COH (X2A') and Cl (X2P). Photodissociation along C-O cleavage resulting in Cl3C (X2A') and OH (X2Π) has to overcome a barrier of about 0.8 eV (13A'', 11A'') and 1.2 eV (13A') because the low-lying excited states 11A'', 13A' and 13A'' become repulsive only after elongating the C-O bond by about 0.3 Å.

Keywords: Multireference configuration interaction; DFT; Ab initio calculations; Photolysis; Chlorinated alcohols; Radicals; Photodissociation.

References: 24 live references.