Journal of Physical Chemistry A, Vol.113, No.16, 4208-4212, 2009
Rotational, Steric, and Coriolis Effects on the F plus HCl -> HF plus Cl Reaction on the 1(2)A' Ground-State Surface
We present a quantum study of the reaction F(P-2) + HCl(X-1 Sigma(+)) -> HF(X-1 Sigma(+)) + Cl(P-2) on a recently computed 1(2)A' ground-state surface, considering HCl in the ground vibrational state, with up to 16 rotational quanta j(0). We employ the real wavepacket (WP) and flux methods for calculating coupled-channel (CC) and centrifugal-sudden (CS) initial-state probabilities up to J = 80 and 140, respectively. We also report CC and CS ground-state cross sections and CS excited-state cross sections and discuss the dynamics analyzing WP time evolutions. The HCl rotation highly enhances reaction probabitities and cross sections, as it was previously found for probabilities at J <= 4. CS errors depend on j(0), on its z projection K-0, and on the collision energy and are small at j(0) = 0 and 16 but large at j(0) = 8. Differences between CC and CS results are associated with the reaction stereodynamics and energetics. Steric effects favor indeed the overcoming of the potential barrier and a linearly dominated mechanism. Attractive Coriolis couplings favor instead the energy flow from the HCl rotation to the F-H---Cl reactive vibration. WP snapshots confirm and explain the HCl rotational effects, because the density into the nearly collinear F-H---Cl product channel increases remarkably with j(0). Finally, our CS rate constant is underestimated with respect to the experiment, pointing out the need of more accurate multisurface and CC calculations.