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The multiphoton absorption and decomposition of CDC13 induced by TEA-C02 laser pulses have been studied at low pressures of CDC13 (0.3 Torr) and with the addition of CHC13 and Ar as bath gases. The laser absorption cross section was also measured as a function of incident fluence in the range 0.01-0.7 J/cm1 2. The reaction probability per pulse was measured at fluences of 7-60 J/cm2 as was the effect of added CHC13 and Ar at 20 and 33 J/cm2. The experimental results were modeled with a master equation with explicit consideration of rotational and anharmonic bottlenecks. The calculations in the high-pressure region allowed obtainment of information about the energy transferred by collision of the vibrationally excited CDC13 with CHC13 and Ar. An energy-dependent value of

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The thermal reaction of transl,2-dichloro-3,3-difluorocyclopropane has been studied from 192.8 to 242.7°. The reaction is first order, homogeneous, and proceeds by two pathways to yield trans-l,3-dichloro-3,3-difluoropropene and cisl,2-dichloro-3,3-difíuorocyclopropane. The overall and the individual rate constants were calculated as log &t(sec-1) = (14.34 ± 0.23) -(42,635 ± 310)/RT, log ktrans-propene = (14.06 ± 0.25) -(42,236 ± 230)/RT, and log kcis.cyclopropane = (14.20 ± 0.74) -(43,818 ± 790) ART. The geometrical isomerization is interpreted on the basis of a diradical mechanism while for the structural isomerization a concerted process with chlorine migration is suggested. The influence of both chlorine and fluorine substitution on the activation energies is discussed mainly in terms of an increased ring strain. The synthesis of the reactant and the identification of the reactant and products is also reported.

The photolysis of C2F51 with CF3COOH in the temperature range 473-533 K was studied in the gas phase.Evidence is presented that supports a complex mechanism for the formation of CzFsH through the H-atom abstraction reaction from CFaCOOH by CzFs radicals as well as the participation of 1(2P*,2).

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The reaction of CF3 radicals with Ha0 (D20) has been studied over the range of 533-723 K using the photolysis and the pyrolysis of CFJ as the free radical source. Arrhenius pa- where klkE/* is in ~r n~'~/ r n o l~'~-s~~~ and B = 2.303RT/cal/mol. The activation energy and the primary kinetic isotope effect have been compared with those derived from the BEBO method.

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