Quantum mechanical differential and integral cross sections for the C(1D) + H2(ν = 0, j = 0) → CH(ν′, j′) + H reaction

Abstract

Accurate quantum dynamics calculations for the C((1)D) + H2 reaction are performed using a real wave packet approach with full Coriolis coupling. The newly constructed ZMB-a ab initio potential energy surface [Zhang et al., J. Chem. Phys. 140, 234301 (2014)] is used. The integral cross sections (ICSs), differential cross sections (DCSs), and product state distributions are obtained over a wide range of collision energies. In contrast to previous accurate quantum dynamics calculations on the reproducing kernel Hilbert space potential energy surface, the present total ICS is much larger at low collision energies, yielding larger rate coefficients in better agreement with experiment and with slight inverse temperature dependence. Meanwhile, interesting nonstatistical behaviors in the DCSs are revealed. In particular, the DCSs display strong oscillations with the collision energy; forward biased product angular distribution appears when only small J partial wave contributions are included; alternate forward and backward biases emerge with very small increments of collision energy; and the rotational state-resolved DCSs show strong oscillations with the scattering angle. Nevertheless, the total DCSs can be roughly regarded as backward-forward symmetric over the whole energy range and are in reasonably good agreement with the available experimental measurements.

Dynamical importance of van der Waals saddle and excited potential surface in C(1D)+D2 complex-forming reaction

“…In particular, the calculated results on our and PESs at higher collision energies are consistent with the observations of the crossed-beam experiments2425, in which the product angular distributions are found to be forward–backward symmetric. It should be noted that the calculated DCSs on the PES, either RKHS or ZMB-a, are nearly forward–backward symmetric252736; however previous calculations show that the addition of the contribution of the BJHL PES37 leads to a forward bias in DCS3842, in contradiction to experiment, indicating that the present PES constructed by us is more accurate than the BJHL PES.…”

“…Although there are other PESs and subsequent dynamical calculations2829, the RKHS PES is the most widely used in dynamical studies273031323334. Most recently, a highly accurate global ab initio PES (or Zhang-Ma-Bian-a (ZMB-a)) has been constructed by our group35, which is unique in the accurate description of the regions of vdW interactions and around conical intersections (CIs), and further dynamical calculations36 performed on this PES for the C( 1 D )+H 2 reaction confirm its accuracy. On the other hand, the excited-state PES may play an important role, and the only reported global PES is the Bussery-Honvault-Julien-Honvault-Launay (BJHL) surface constructed by Bussery-Honvault et al .…”

Ring-Polymer Molecular Dynamics for the Prediction of Low-Temperature Rates: An Investigation of the C(1D) + H2 Reaction

“…50,51 However, these surfaces are less well validated -different topologies were obtained which resulted in a noticeable spread of rate values. 37,57 Perhaps more importantly, a slight negative temperature dependence was observed, as opposed to the presently employed surface, which suggests that the agreement with the present experimental results would be worse. Finally, the most obvious explanation is the adiabatic limit used in the present simulations.…”

Quantum reaction dynamics of C(1D) + HD → CH(CD) + D(H) on the ground state potential energy surface

“…Besides, the calculated vibrational energy levels are also in better agreement with experiment than those computed on the BHL potential. QCT and QM studies for the reaction of C + H 2 (D 2 ) have been performed on this potential and obtained interesting results. Thus, to obtain more insight into the title reaction, it is desirable to investigate the quantum dynamics on this new constructed PES.…”