Experimental absolute cross-sections for the reaction F+D-2 at collision energies 90-240 meV

Absolute differential and integral cross-sections for the DF(upsilon(f)=0-4) vibrational products of the F + D-2(upsilon(i)=0j(i)=0-2) --> DF(upsilon(f)) + F reaction have been evaluated from the time-of-flight spectra measured in high-resolution crossed molecular beam scattering experiments at five collision energies within the range 90-240 meV. The observed rise of the total reactive cross-section with increasing collision energy can be fitted with an empirical, modified line-of-centers model, yielding an activation energy of 1.8 kcal.mol(-1). Remarkably pronounced angular structures are observed in the vibrationally resolved differential reactive cross-sections, especially for the largest accessible vibrations, upsilon(f) = 3 and upsilon(f) = 4. The experimental absolute cross-sections are compared with the results of previously reported quantum mechanical and quasiclassical trajectory calculations on the most recent potential energy surfaces for the F + D-2 system. An overall excellent agreement is found within the experimental uncertainty. However, some significant differences are also apparent, especially at the lowest collision energies studied.