Photodissociation of CF<SUB>2</SUB>Br<SUB>2</SUB> at 248 nm: a time-resolved absorption study

Photodissociation of CF2Br2 at 248 nm has been studied in the gas phase using time-resolved optical absorption spectroscopy. A transient absorption spectrum in the range of 200-320 nm with &#955; max &#8776; 260 nm is observed and has been assigned to the primary photodissociation product, the CF2Br radical. The absorption cross section of this radical at 260 nm has been found to be (1.05 &#177; 0.2) &#215; 10-18 cm2 molecule-1. The rate constant for CF2Br dimerization is evaluated to be (3.0 &#177; 0.6) &#215; 10-12 cm3 molecule-1 s-1. Laser fluence dependence in the secondary photodissociation of CF2Br radical is discussed