Fine structure of the CCl₃ UV absorption spectrum and CCl₃ kinetics

The UV gas-phase spectrum of CCl3 was recorded in the range 220-300 nm using pulse radiolysis of CHCl3/SF6 or CCl4/Ar gas mixtures. The UV spectrum exhibits a pronounced vibrational fine structure which is assigned to transition into the (C2A1'(3s)) Rydberg state. The vibronic progression has a band origin around 250 nm and the spacing of 569 +/- 63 cm-1 is ascribed to excitation of the out-of-plane bending mode. The absorption cross section with a maximum of sigma = (1.02 +/- 0.16) x 10(-17) cm2 molecule-1 at 224.80 +/- 0.16 nm was determined relative to sigma(CH3) and sigma(CH3O2). The rate constants for CCl3 + CCl3 + M --> C2Cl6 + M and CCl3 + Cl + M --> CCl4 + M are (5.9 +/- 1.3) x 10(-12) and (6.5 +/- 1.4) x 10(-11) cm3 molecule-1 s-1, respectively, at 298 +/- 2 K and 1 atm total pressure.