Product polarization and mechanism of Li+HF(v=0, j=0)→LiF (v’, j’)+H collision reaction

A state-to-state dynamics analysis for the Li+HF (v = 0, j = 0)→LiF (v’, j’)+H collision reaction has been performed through quasiclassical trajectory (QCT) calculations. It is found that the differential cross section (DCS) of the LiF products from the title reaction is preferentially backward scattering for v’=0, yet forward scattering for v’=1 and 2. For v’=3, the DCS exhibits forward, backward, and sideways scatterings. The variation of the internuclear distances and angles along the propagation time reveals that more than 99.08% of reaction trajectories undergo the direct reaction mechanism. The values of the polarization parameters a_1-¹ and a₀² demonstrate that the product rotational angular moment j’ is not only aligned perpendicular to the reagent relative velocity vector k, but also oriented along the negative y axis. These product polarization results agree well with the recent quantum mechanical studies. The mechanism of these results was proposed and discussed in detail.