Dynamics of Nonadiabatic Reactions. 4. Effect of Enhanced Collision Energy in the Four-Center Reaction F2 + Na2 ---> F + NaF + Na*

Article abstract of DOI:10.1021/j100349a011

The four-center reaction F2 + Na2 ---> F + NaF + Na(3²P) has been studied in a crossed molecular-beam experiment.The excitation function for the production of this electronically excited state has been measured over two ranges of collisiomn energy -5.8-6.8 and 9.4-15.4 kcal/mol.This cross section has been scaled for comparison with that of the three-center reaction F + Na2 ---> NaF + Na*(³²P) (see the experimental results reported in the preceeding paper in this issue).The three-center reaction cross section to form Na*(3²P) is also a rising function of collision energy.The three-center reaction to form Na*(3²P) is connected adiabatically to the ground reactant state while the four-center reaction increases from ca. 1 to 8 Angstroem², while that for the three-center reaction increases from ca.4 to 125 Angstroem².Both reactions appear to involve a barrier to the production of the Na*(3²P).In the case of four-center reaction, the steeply rising excitation function may result from the changing nonadiabatic behavior with increasing collision energy.