SCRIBANO Yohann
Fonction : Maître de conférences HDR
Organisme : UM2
Maître de Conférences (HDR)
Directeur(trice) de thèse de :
DUPUY L.,
Thème de Recherche: Astrophysique Stellaire
yohann.scribano
umontpellier.fr
0467144535
Bureau: 7, Etg: 4, Bât: 13  Site : campus Triolet
Activités de Recherche: 
Théories et Simulations en Dynamique Quantique et Spectroscopie Moléculaire 
Projets de Recherche: 
PI du projet ANR "HyTRAJ" (20202024) Partenaire du projet 80PrimeCNRS "AlgDynQua" 
Participation(s) à Projets: 

Domaines de Recherche:  Physique/Physique/Agrégats Moléculaires et Atomiques
 Physique/Physique/ChimiePhysique
 Physique/Physique/Physique Numérique

Dernieres productions scientifiques :


Hybrid quantumclassical trajectories method for multidimensional reactive scattering
Auteur(s): Dupuy L., Scribano Y.
Conference: Réunion annuelle 2021 du GDR THEMS (Toulouse, FR, 20211109)
Résumé: The accurate description of quantum effects, particularly quantum tunneling[1], in bimolecular chemical reactions constitutes one of the major goals of theoretical chemistry. Due to an unfavorable scaling law, exact quantum scattering methods lead to expensive and often unfeasible simulations when considering chemical systems with a large number of degrees of freedom. Moreover, at low temperature quantum effects often do not represent a small correction to classical calculations, but contrariwise are essential to obtain quantitative results.
In this talk, I will show the feasibility of accurate quantum stationary scattering simulations for high dimensional systems using hybrid quantumclassical trajectories[2]. The configuration space is partitioned in one reaction coordinate going from reactants to products along which trajectories reproduce quantum effects, and bath coordinates with small amplitude motion which are treated classically[3]. Quantization of bath modes by a semiclassical phasespace sampling approximation based on WignerWeyl mapping allows to accurately reproduce quantum structure effects such as reaction thresholds. As was acknowledged many years ago [4], when the motion along the reaction coordinate is sufficiently slow compared to perpendicular motion, both subsystems undergo adiabatic evolution. By taking advantage from the local character of trajectory dynamics, I will illustrate how onthefly conversion from positionmomenta to actionangle representation for bath coordinates in specific regions of vibrational adiabaticity leads to a computationally efficient scheme[5].



Direct time delay calculation from quantum trajectory propagation based method: Application to onedimensional ketene isomerization
Auteur(s): Dupuy L., Parlant Gerard, Poirier Bill, Scribano Y.
(Document sans référence bibliographique) 20220218
Résumé: Resonances are ubiquitous in chemical reactions and can fully control the reactivity explaining the permanent ongoing high interest for this research's field. We report an efficient approach to accurately determine time delay of resonant reactive scattering processes described by a onedimensional reactive scattering model. Our approach is based on the recent trajectoryensemble reformulation of quantum mechanics, as recently proposed by one of the authors (Poirier). The time delay, as defined by F.T. Smith [Phys. Rev. \textbf{118}, 349 (1960)], is directly computed from the propagation of the quantum trajectory. We applied this new method on some simple analytical chemical reactions models and obtained an excellent agreement. Our approach is highly robust and accurate over all the energy domain and does not suffer from any adjustment problem since we are free from any parametrisation of complex absorbing potentials, a wellknow difficulty of ABCDVR methods. The quantum trajectory represents a very promising tool for the study of complex chemical reactions characterized by resonant tunneling effect.



Multidimensional tunneling through a reaction pathway from a stationary quantum trajectory formalism
Auteur(s): Dupuy L., Scribano Y.
(Document sans référence bibliographique) 20211006
Résumé: In this work we propose an exact derivation of the Hamilton formulation of quantum mechanical stationary scattering in onedimensional curved space.



Smolyak representations with absorbing boundary conditions for reaction path Hamiltonian model of reactive scattering
Auteur(s): Dupuy L., Lauvergnat David, Scribano Y.
(Article) Accepté:
Chemical Physics Letters, vol. p.XXX (2021)
DOI: 10.1016/j.cplett.2021.139241
Résumé: In this work, we present the efficient combination of Smolyak representations with time indepen
dent quantum mechanical approach using absorbing boundary conditions for the cumulative reac
tion probability calculations of a multidimensional reactive scattering problem. Our approach uses
both kinds of Smolyak representations (finite basis and grid) which drastically reduces the size of
the basis representation for the cumulative reaction operator. The cumulative reaction probability
is thus obtained by solving the eigenvalue problem within the context of reaction path Hamiltonian
using the compact Smolyak basis combined with an iterative Lanczos algorithm. Benchmark cal
culations are presented for reactive scattering models with a linear reaction coordinate and applied
to a 25D model highlighting the efficiency of the present approach for multidimensional reactive
processes.



Quantum dynamics with trajectories: onedimensional scattering problems
Auteur(s): Dupuy L., Scribano Y.
Conference: Algorithmes en dynamique quantique moléculaire Algorithms in Quantum Molecular Dynamics (AlgDynQua) (Marseille, FR, 20200914)
Résumé: We present recent progress on quantum trajectories method for one dimensional resonant reactive scattering processes.

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