Resonance features in the isotopic branching ratios for the F + HD reaction

Quantum mechanical cross sections for the two channels of the F + HD reaction, calculated and published by Zhang et al. (J. Chem. Phys. 2000, 112, 9802) employing the potential energy surface of Stark and Werner (J. Chem. Phys. 1996, 104, 6515) were used to calculate ratios of cross sections and ratios of rate constants under a variety of initial conditions. It is shown that, for the range of low collision energies at a rotational temperature of 50 K for which a resonance peak for the HF + D product channel was observed by Skodje et al. (J. Chem. Phys. 2000, 112, 4536; Phys. Rev. Lett. 2000, 85, 1206), both experimentally and theoretically, and even more so for higher rotational temperatures, there are obvious advantages in presenting results in terms of ratios of cross sections, rather than in terms of absolute cross sections. Results for ratios of cross sections for collision energies higher than the low-energy range of the resonance peak, as well as for ratios of rate constants over a wide temperature range, are presented and discussed.