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J. phys. Chem. 1902, 86, 4678-4683
not close packed, but randomly dispersed on the surface with the hydrocarbon backbone nonlinear and not oriented preferentially along the surface normal. The infrared spectra of these two systems, by comparison of the relative intensities of the asymmetric methylene C-H stretch, d-(.lr), to the asymmetric methyl C-H stretch, ra-, support the conclusion that the solution monolayers are a thinner assembly on the average,mwell bound to the
surface through the carboxylate group (viz., Figure 3), but with the majority of the methylene chain of each molecule lying in the plane of the surface. We conclude from these data that solution-deposited fatty acid monolayers do not adsorb to form highly ordered structures; Le., solution monolayers are much less dense and much more disordered than LB monolayers.
(28)The shift in the position of the surface plasmon resonance angle reflection minimum obsked for an LB monoliyer ie much greater t h k that for solution monolayers. This implies that the latter monolayer is proportionally thinner and/or patchier. J. D.Swalen and M.R. philpott, private communication.
Acknowledgment. We thank the followine individuals for helpful teihnical assistance and discus~ons: Ma R. Phibott, D. J. Pocker, - . J. F. Rabolt, N. Schlotter, J. Sunzeri, and J. D. Swalen.
Kinetics of the Reactions of CF, with O(,P) and O2 at 295 K K. R. Ryan' and 1. C. Plumb CSIRO Dlvlslon of Applied Mysics, Sydney, Australia 2070 (Received:June 1, 1982)
The reactions of CF3with O(3P)and 02 have been studied at 295 K by using discharge flow methods with helium as the bath gas. In one set of experiments two microwave discharges were used to produce independently sources of 0 atoms and CF3radicals. Under the conditions employed negligible consumption of 0 atoms occurred by reaction with CF3,thus allowing the rate coefficient to be obtained by observing the pseudo-first-order decay of CF3. These measurements gave a rate coefficient of (3.1 f 0.8) X lo-" cm3s-l for the reaction CF3+ 0 CF20 + F at 295 K. The rate coefficient for the reaction between O2and CF3was found to increase from 2.2 X to 1.24 X cm3s-l as the [He] increased from 1.6 X 1018to 2.7 X 10'' cmd3. The possibility of two pathways was examined, namely, CF3 + O2 CF3O2 and CF3 + O2 CF20 + FO. It was found that
