Crossed molecular beam study of the F+D₂(v=1, j=0) reaction^†

The reaction dynamics of the fluorine atom with vibrationally excited D₂(v=1, j=0) was investigated using the crossed beam method. The scheme of stimulated Raman pumping was employed for preparation of vibrationally excited D₂ molecules. Contribution from the reaction of spin-orbit excited F*(²P_1/2) with vibrationally excited D₂ was not found. Reaction of spin-orbit ground F(²P_3/2) with vibrationally excited D₂ was measured and DF products populated in v′=2, 3, 4, 5 were observed. Compared with the vibrationally ground reaction, DF products from the vibrationally excited reaction of F(²P_3/2)+D₂(v=1, j=0) are rotationally “hotter”. Differential cross sections at four collision energies, ranging from 0.32 kcal/mol to 2.62 kcal/mol, were obtained. Backward scattering dominates for DF products in all vibrational levels at the lowest collision energy of 0.32 kcal/mol. As the collision energy increases, angular distribution of DF products gradually shifts from backward to sideway. The collision-energy dependence of differential cross section of DF(v′=5) at forward direction was also measured. Forward-scattered signal of DF(v′=5) appears at the collision energy of 1.0 kcal/mol, and becomes dominated at 2.62 kcal/mol.