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Accueil > Séminaires > Année 2024 > Séminaire de Hua Guo (31 mai)

Séminaire de Hua Guo (31 mai)

par Martrenchard-Barra Séverine - 14 mai

Probing Transition State Dynamics via Anion Photodetachment : Theoretical Perspective

Due to the flitting nature of the transition state, information on its dynamics is often difficult to obtain. In cases where the geometry of the saddle point on the reactive potential energy surface is close to the equilibrium geometry of a stable anion, it is possible to gain detailed knowledge of the transition state dynamics via photodetachment of the anion. The vertical transition from the anionic to the neutral state via the ejection of the electron prepares a wave packet near the transition state, which evolves in time to report the subsequent dynamics. Here, we discuss our recent effort to understand the quantum dynamics of photodetachment of several anions, including H2CC-,[1] H2O-F-,[2] CH3OH-F-,[3] NH3-F-,[4] and SO2-OH-,[5] which shed light on the transition state dynamics in both unimolecular and bimolecular reactions and role of resonances.

[1] DeVine, J. A. ; Weichman, M. L. ; Laws, B. ; Chang, J. ; Babin, M. C. ; Balerdi, G. ; Xie, C. ; Malbon, C. L. ; Lineberger, W. C. ; Yarkony, D. R. ; Field, R. W. ; Gibson, S. T. ; Ma, J. ; Guo, H. ; Neumark, D. M., Encoding of vinylidene isomerization in its anion photoelectron spectrum. Science 2017, 358 (6361), 336-339.
[2] Otto, R. ; Ma, J. ; Ray, A. W. ; Daluz, J. S. ; Li, J. ; Guo, H. ; Continetti, R. E. Imaging dynamics on the F + H2O → HF + OH potential energy surfaces from wells to barriers. Science 2014, 343, 396-399.
[3] Weichman, M. L. ; DeVine, J. A. ; Babin, M. C. ; Li, J. ; Guo, L. ; Ma, J. ; Guo, H. ; Neumark, D. M., Feshbach resonances in the exit channel of the F + CH3OH → HF + CH3O reaction observed using transition-state spectroscopy. Nat. Chem. 2017, 9, 950-955.
[4] Babin, M. C. ; DeWitt, M. ; Lau, J. A. ; Weichman, M. L. ; Kim, J. B. ; Song, H. ; Guo, H. ; Neumark, D. M., Observation of resonances in the transition state region of the F + NH3 reaction using anion photoelectron spectroscopy. Nat. Chem. 2023, 15 (2), 194-199.
[5] Yuan, D.-F. ; Liu, Y. ; Trabelsi, T. ; Zhang, Y.-R. ; Li, J. ; Francisco, J. S. ; Guo, H. ; Wang, L.-S., Probing the dynamics and bottleneck of the key atmospheric SO2 oxidation reaction by the hydroxyl radical. Proc. Natl. Acad. Sci. U. S. A. 2024, 121, e2314819121.