Thhe kinetics of CF3 and CH3 radical reactions have been investigated using the VLPO method. The reactions of interest were radical recombination and metathetical halogenation (Br2, Cl2). In addition to yielding gas-phase reaction rates, these studies pointed out the importance fo gas-surface interactions in the chemistry. The VPLO technique was also used to investigate a radical-surface reaction: the reaction of the CF3 radicals on a silicon oxide surface. The latter study revealed that H2O on the surface plays a major role in the chemistry. The surface reaction was studied as functions of surface temperature (320-530 K) and CF3 concentration. Keywords: Very low-pressure pyrolysis; Laser induced kinetics; Radical surface chemistry; Chlorine; Bromine; Fluorine; and Methane.