RT Journal Article
T1 Li + HF and Li + HCl Reactions Revisited I: QCT Calculations and Simulation of Experimental Results
A1 Menéndez Carbajosa, Alicia Marta
A1 Garcia Para, Ernesto
A1 Lara Garrido, Manuel
A1 García Jambrina, Pablo
A1 Aoiz Moleres, Francisco Javier
AB The Li + HF and Li + HCl reactions share some common features. They have the same kinematics, relatively small barrier heights, bent transition states, and are both exothermic when the zero point energy is considered. Nevertheless, the pioneering crossed beam experiments by Lee and co-workers in the 80s (Becker et al., J. Chem. Phys. 1980, 73, 2833) revealed that the dynamics of the two reactions differ significantly, especially at low collision energies. In this work, we present theoretical simulations of their results in the laboratory frame (LAB), based on quasiclassical trajectories and obtained using accurate potential energy surfaces. The calculated LAB angular distributions and time-of-flight spectra agree well with the raw experimental data, although our simulations do not reproduce the experimentally derived center-of-mass (CM) differential cross section and velocity distributions. The latter were derived by forward convolution fitting under the questionable assumption that the CM recoil velocity and scattering angle distribution were uncoupled, while our results show that the coupling between them is relevant. Some important insights into the reaction mechanism discussed in the article by Becker et al. had not been contrasted with those that can be extracted from the theoretical results. Among them, the correlation between the angular momenta involved in the reactions has also been examined. Given the kinematics of both systems, the reagent orbital angular momentum, 𝓁𝑙, is almost completely transformed into the rotation of the product diatom, j′. However, contrary to the coplanar mechanism proposed in the original paper, we find that the initial and final relative orbital angular momenta are not necessarily parallel. Both reactions are found to be essentially direct, although about 15% of the LiFH complexes live longer than 200 fs.
PB ACS Publications
SN 1089-5639
SN 1520-5215
YR 2023
FD 2023-08-14
LK https://hdl.handle.net/20.500.14352/105874
UL https://hdl.handle.net/20.500.14352/105874
LA eng
NO Marta Menéndez, Ernesto Garcia, Manuel Lara, Pablo G. Jambrina, and F. Javier Aoiz. Li + HF and Li + HCl Reactions Revisited I: QCT Calculations and Simulation of Experimental Results .The Journal of Physical Chemistry A 2023 127 (33), 6924-6944 DOI: 10.1021/acs.jpca.3c03763
NO Published as part of The Journal of Physical Chemistry virtual special issue “Marsha I. Lester Festschrift”.
DS Docta Complutense
RD 30 ago 2024