Dispersión reactiva de haces moleculares : variación de la reacción eficaz reactiva con la energía en la reacción C2 H5 I+ K-KI+C2 H5

Tesis - Universidad Complutense de Madrid, 1981.Fac. de Ciencias QuímicasTRUEProQuestpu

Digitalización del laboratorio de Química Física I en tiempos de COVID-19

Depto. de Química FísicaFac. de Ciencias QuímicasFALSEsubmitte

Temperature dependence of the rate coefficient of formation of CN radical from C + NH

Rate coefficients of the complex-forming C + NHH + CN reaction have been calculated at temperatures ranging from 5 K to 800 K using quasi-classical trajectories on a potential energy surface which accurately describes the attractive long-range interaction, along with results using two capture models. In contrast with the constant value recommended in astrochemical databases, a steep decrease of the rates has been found up to 150 K, and then they tends to be nearly constant. Such behavior is analyzed in terms of the rovibrational state-selected rate coefficients and cross sections singling out the role played by the rotational excitation of the initial diatom. The effect of the electronic degeneracy is also discussed.We thank Prof. A.J.C. Varandas for making available to us the DMBE potential energy surface and the Oklahoma University Supercomputing Center for Education & Research (OSCER) and the European Grid Infrastructure (EGI) through COMPCHEM Virtual Organization for providing computing resources and services. The authors also acknowledge the financial support from the MINECO/FEDER of Spain under grants PGC2018-096444-B-I00, PID2019-107115 GB-C21 and FIS2017-83473-C2

Li + HF and Li + HCl Reactions Revisited I: QCT Calculations and Simulation of Experimental Results

Published as part of The Journal of Physical Chemistry virtual special issue “Marsha I. Lester Festschrift”.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, , 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.Depto. de Química FísicaFac. de Ciencias QuímicasTRUEpubDescuento UC