scholarly journals Stereodynamical Control of Nonadiabatic Quenching Dynamics of OH(A2S+) by H2: Full-Dimensional Quantum Dynamics

2021 ◽  
Author(s):  
Bin Zhao ◽  
Shanyu Han ◽  
Christopher Malbon ◽  
Uwe Manthe ◽  
David Yarkony ◽  
...  
Keyword(s):  
Quantum Dynamics ◽  
Branching Ratio ◽  
Nonadiabatic Dynamics ◽  
Energy Matrix ◽  
Elastic Channel ◽  
Potential Energy Matrix ◽  
Electronically Excited ◽  
Oppenheimer Approximation ◽  
Dynamical Method ◽  
Good Agreement

Abstract The breakdown of the Born-Oppenheimer approximation is omnipresent in chemistry, but our detailed understanding of the nonadiabatic dynamics is still incomplete. In the present work, nonadiabatic quenching of electronically excited OH(A2S+) molecules by H2 molecules is investigated by a full-dimensional quantum dynamical method using a high quality diabatic potential energy matrix. Good agreement with experiment is found for the OH(X2P) ro-vibrational and L-doublet distributions. Furthermore, the nonadiabatic dynamics is shown to be controlled by stereodynamics, namely the orientation of the two reactants. The uncovering of a major (in)elastic channel, neglected in all previous analyses, resolves a long-standing experiment-theory disagreement concerning the branching ratio of the two electronic quenching channels.

scholarly journals Full-dimensional quantum stereodynamics of the non-adiabatic quenching of OH(A2Σ+) by H2

2021 ◽  
Author(s):  
Bin Zhao ◽  
Shanyu Han ◽  
Christopher L. Malbon ◽  
Uwe Manthe ◽  
David. R. Yarkony ◽  
...  
Keyword(s):  
Quantum Dynamics ◽  
Previous Analysis ◽  
Branching Ratio ◽  
Energy Matrix ◽  
Elastic Channel ◽  
Electronically Excited ◽  
Oppenheimer Approximation ◽  
Electronic Motion ◽  
Adiabatic Dynamics ◽  
Good Agreement

AbstractThe Born–Oppenheimer approximation, assuming separable nuclear and electronic motion, is widely adopted for characterizing chemical reactions in a single electronic state. However, the breakdown of the Born–Oppenheimer approximation is omnipresent in chemistry, and a detailed understanding of the non-adiabatic dynamics is still incomplete. Here we investigate the non-adiabatic quenching of electronically excited OH(A2Σ+) molecules by H2 molecules using full-dimensional quantum dynamics calculations for zero total nuclear angular momentum using a high-quality diabatic-potential-energy matrix. Good agreement with experimental observations is found for the OH(X2Π) ro-vibrational distribution, and the non-adiabatic dynamics are shown to be controlled by stereodynamics, namely the relative orientation of the two reactants. The uncovering of a major (in)elastic channel, neglected in a previous analysis but confirmed by a recent experiment, resolves a long-standing experiment–theory disagreement concerning the branching ratio of the two electronic quenching channels.

High-Fidelity First Principles Nonadiabaticity: Diabatization, Analytic Representation of Global Diabatic Potential Energy Matrices, and Quantum Dynamics

2021 ◽  
Author(s):  
Yafu Guan ◽  
Changjian Xie ◽  
David R. Yarkony ◽  
Hua Guo
Keyword(s):  
Potential Energy ◽  
Excited States ◽  
First Principles ◽  
Quantum Dynamics ◽  
Chemical Processes ◽  
High Fidelity ◽  
Nonadiabatic Dynamics ◽  
Electronically Excited States ◽  
Electronically Excited ◽  
Oppenheimer Approximation

Nonadiabatic dynamics, which goes beyond the Born-Oppenheimer approximation, has increasingly been shown to play an important role in chemical processes, particularly those involving electronically excited states. Understanding multistate dynamics requires...

Ultrafast nonadiabatic dynamics probed by nitrogen K-edge absorption spectroscopy

2020 ◽  
Vol 22 (5) ◽  
pp. 2667-2676 ◽  
Author(s):  
T. Northey ◽  
J. Norell ◽  
A. E. A. Fouda ◽  
N. A. Besley ◽  
M. Odelius ◽  
...  
Keyword(s):  
Excited States ◽  
Quantum Dynamics ◽  
Degrees Of Freedom ◽  
Nonadiabatic Dynamics ◽  
Edge Structure ◽  
Strongly Coupled ◽  
X Ray ◽  
Electronically Excited ◽  
Dynamics Simulations ◽  
X Ray Absorption

Quantum dynamics simulations are used to simulate the ultrafast X-ray Absorption Near-Edge Structure (XANES) spectra of photoexcited pyrazine including two strongly coupled electronically excited states and four normal mode degrees of freedom.

Spectroscopy, polarization and nonadiabatic dynamics of electronically excited Ba(Ar)n clusters: Theory and experiment

1996 ◽  
Vol 104 (10) ◽  
pp. 3651-3663 ◽  
Author(s):  
A. I. Krylov ◽  
R. B. Gerber ◽  
M. A. Gaveau ◽  
J. M. Mestdagh ◽  
B. Schilling ◽  
...  
Keyword(s):  
Nonadiabatic Dynamics ◽  
Electronically Excited ◽  
Theory And Experiment

Resonant and non-resonant contributions of B → K∗(p1,𝜖1){Kπ,ππ,KK} decay modes

2019 ◽  
Vol 34 (06) ◽  
pp. 1950043
Author(s):  
Mahboobeh Sayahi
Keyword(s):  
Experimental Data ◽  
Perturbation Theory ◽  
Chiral Perturbation Theory ◽  
Branching Ratio ◽  
Heavy Meson ◽  
Chiral Perturbation ◽  
Decay Modes ◽  
Qcd Factorization ◽  
Three Body ◽  
Good Agreement

In this paper, the non-leptonic three-body decays [Formula: see text], [Formula: see text], [Formula: see text] are studied by introducing two-meson distribution amplitude for the [Formula: see text], [Formula: see text] and [Formula: see text] pairs in naive and QCD factorization (QCDF) approaches, such that the analysis is simplified into quasi-two body decays. By considering that the vector meson is being ejected in factorization, the resonant and non-resonant contributions are analyzed by using intermediate mesons in Breit–Wigner resonance formalism and the heavy meson chiral perturbation theory (HMChPT), respectively. The calculated values of the resonant and non-resonant branching ratio of [Formula: see text], [Formula: see text] and [Formula: see text] decay modes are compared with the experimental data. For [Formula: see text] and [Formula: see text], the non-resonant contributions are about 70–80% of experimental data, for which the total results by considering resonant contributions are in good agreement with the experiment.

ROUGHENING TRANSITION IN BRANCHING POLYMERS

Fractals ◽  
2003 ◽  
Vol 11 (supp01) ◽  
pp. 29-36 ◽  
Author(s):  
LIACIR S. LUCENA ◽  
LUCIANO R. DA SILVA ◽  
STÉPHANE ROUX
Keyword(s):  
Phase Diagram ◽  
Phase Boundary ◽  
Branching Ratio ◽  
Direct Numerical Simulations ◽  
Branched Polymers ◽  
Heterogeneous Environment ◽  
Original Algorithm ◽  
Roughening Transition ◽  
Analytic Computation ◽  
Good Agreement

A growth model, introduced to model the development of branched polymers in an heterogeneous environment, gives rise to clusters whose boundary is either faceted or rough. We study the transition between these two morphologies as a function of the parameters of the model, impurity concentration and branching ratio. The phase diagram is first obtained by direct numerical simulations, using an original algorithm, based on a self-regulated search of a critical point. Then an analytic computation of the phase boundary is proposed based on a simple approximation. The obtained phase boundary is in good agreement with the numerical results. The nature of the transition is discussed.

A DYNAMICAL METHOD FOR DETERMINING THE ELASTIC CONSTANTS AND RELAXATION PARAMETERS IN NEMATIC LIQUID CRYSTALS

2000 ◽  
Vol 14 (04) ◽  
pp. 139-146 ◽  
Author(s):  
EMIL PETRESCU ◽  
CORNELIA MOTOC ◽  
DOINA MANAILA
Keyword(s):  
Magnetic Field ◽  
Liquid Crystals ◽  
Elastic Constants ◽  
Light Transmission ◽  
Nematic Liquid Crystals ◽  
Relaxation Parameters ◽  
Nematic Director ◽  
Dynamical Method ◽  
The Magnetic Field ◽  
Good Agreement

The theoretical model proposed by Pieranski et al.3 to describe the phenomena occurring in nematic liquid crystals when the magnetic field is suddenly varied was extended by considering higher powers of the distortion angle for the nematic director. Equations giving the time evolution of the number of extinctions in the light transmission were obtained. These equations depend on some relaxation parameters (the time constants τA and τB intervening when the magnetic field was switched "on" or "off", respectively) and on the ratio of elastic constants. The equations were solved numerically and good agreement with the experimental data was obtained for the nematic MBBA.

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