The fluorine atomic radical reactions to form molecular fluorine and hydrogen fluoride are examined by time-of-flight mass spectroscopy (TOFMS) and kinetically modeled for various reaction orders. Fluorine radicals are generated from NF3 or F-2 in microwave-generated and low-frequency (LF)-generated plasmas and are passed through flow tubes under various flow, pressure, and dilution conditions. In general, the concentrations of the mass spectroscopically measured products F, F-2, and HF do not depend on the specific wall material (e.g., Teflon, stainless steel, Al, Ni, Al2O3, SiO2); the only variations of [F]/[F-2]/[HF] ratios with wall material are found at pressures below 1 Torr. The most significant changes in these ratios are observed upon varying flow rates and pressures. Specifically, the F relative concentration decreases from similar to80% to similar to20%, and the F-2 relative concentration increases from similar to20% to similar to80%, as the pressure is varied over the range 0.5-10 Torr. In all cases, the HF concentration is found to decrease as the pressure increases. Data suggest that the composition of the tube surface material does not contribute significantly to the generation of F-2; however, since the wall surface carries adsorbed hydrogen sources such as H, H2O, H-2, and OH, it becomes important in the generation of HF. A simple kinetic analysis of the experimental data suggests a combined two-reaction mechanism for F-2 and HF generation: (1) a pseudo-second-order volume reaction (k(v)) to generate F-2, and (2) a zero- or first-order wall reaction (k(w)) to generate HF. Thus, both surface and volume reactions contribute to the overall F atom loss mechanism in the gas flow from the plasma source. The model fits our data best for a k(v)/k(w) ratio of about 75. The reaction order for the loss of F atom is found to be 1.68, while the reaction order for the formation of F-2 is found to be similar to2.