Mixtures of SF 6 with various simple hydrocarbons are irradiated at ≈2 torr by CO 2 laser pulses of power density 10 8 W cm -2, yielding transient visible luminescence from products of hydrocarbon dissociation. Stepwise multiple photon excitation of SF 6 molecules is shown to initiate the rapid sequence of events leading to hydrocarbon dissociation. The most probable mechanism consists of infrared photodissociation of SF 6, the F atoms from which react with the hydrocarbon, yielding C 2 and CH chemiluminescence.