Concerted quantum effects of electronic and nuclear fluxes in molecules

Barth, Ingo; Hege, Hans-Christian; Ikeda, Hiroshi; Kenfack, Anatole; Koppitz, Michael; Manz, J.; Marquardt, Friedrich-Wilhelm; Paramonov, G. K.

doi:10.1016/j.cplett.2009.09.011

Cited by 99 publications

(166 citation statements)

References 39 publications

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“…For reference, illuminating analyses of the mechanisms of electron dynamics in terms of flux densities has been demonstrated recently in refs. [87,88]. Here the snapshot is taken at time t = 0, i.e.…”

Section: Interplay Of Correlated Elastic and Uncorrelated Inelastic Fmentioning

confidence: 99%

Quantum model simulations of attosecond electron diffraction

Baum

Manz

Schild

2010

Sci. China Phys. Mech. Astron.

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Ultrafast diffraction with free attosecond electron pulses promises insight into the four-dimensional motion of charge density in atoms, molecules and condensed matter. Here we consider the quantum dynamics of the electron-electron scattering process on an attosecond time scale. By numerically solving the time-dependent two-electron Schrödinger equation, we investigate the interaction of an incoming keV-range electron wavepacket by the bound electron of an aligned H + 2 molecule, using a one-dimensional model. Our findings reveal the ratio of elastic to inelastic contributions, the role of exchange interaction, and the influence of the molecular electron density to diffraction. Momentum transfer during the scattering process, from the incoming to the bound electron mediated by the nuclei, leaves the bound electron in a state of coherent oscillation with attosecond recurrences. Entanglement causes related state-selective oscillations in the phase shift of the scattered electron. Two scenarios of distinguishable and indistinguishable free and bound electrons yield equivalent results, irrespective of the electronic spins. This suggests to employ the scenario of distinguishable electrons, which is computationally less demanding. Our findings support the possibility of using electron diffraction for imaging the motion of charge density, but also suggest the application of free electron pulses for inducing attosecond dynamics. ultrafast electron diffraction, scattering theory, attosecond dynamics, entanglement, coherence

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Section: Interplay Of Correlated Elastic and Uncorrelated Inelastic Fmentioning

confidence: 99%

Quantum model simulations of attosecond electron diffraction

Baum

Manz

Schild

2010

Sci. China Phys. Mech. Astron.

Self Cite

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“…The electric current and the magnetic dipole moment contain both electronic and nuclear contributions, but when the BO approximation is employed, the electronic contributions identically vanish. This is due to the fact that the ground-state electronic wave function is real for a non-degenerate adiabatic state and therefore the expectation values of the purely imaginary (Hermitian) electric current [23][24][25][26][27][28] and magnetic dipole moment operators vanish [18]. Therefore, VCD appears a fundamentally non-adiabatic (beyond-BO) process, thus requiring a theoretical approach able to explicitly treat the dynamical coupling between electronic and nuclear degrees freedom in molecules.…”

Section: Introductionmentioning

confidence: 99%

Nuclear velocity perturbation theory for vibrational circular dichroism: An approach based on the exact factorization of the electron-nuclear wave function

Scherrer

Agostini

Sebastiani

et al. 2015

The Journal of Chemical Physics

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The nuclear velocity perturbation theory (NVPT) for vibrational circular dichroism (VCD) is derived from the exact factorization of the electron-nuclear wave function. This new formalism offers an exact starting point to include correction terms to the Born-Oppenheimer (BO) form of the molecular wave function, similarly to the complete-adiabatic approximation. The corrections depend on a small parameter that, in a classical treatment of the nuclei, is identified as the nuclear velocity. Apart from proposing a rigorous basis for the NVPT, we show that the rotational strengths, related to the intensity of the VCD signal, contain a new contribution beyond-BO that can be evaluated with the NVPT and that only arises when the exact factorization approach is employed. Numerical results are presented for chiral and non-chiral systems to test the validity of the approach.

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“…However, the "exact" non-BOA wave function for H 2 + (oriented so that the nuclei lie on the z-axis) yields both parallel (z) and transverse (r) components. 4 Even though the quasi-classical EFD agrees well with the "exact" zcomponent, it has no r-component.…”

Section: Discussionmentioning

confidence: 92%

Quasi-Classical Theory of Electronic Flux Density in Electronically Adiabatic Molecular Processes

Diestler

2012

J. Phys. Chem. A

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The standard Born-Oppenheimer (BO) description of electronically adiabatic molecular processes predicts a vanishing electronic flux density (EFD). A previously proposed "coupled-channels" theory permits the extraction of the EFD from the BO wave function for one-electron diatomic systems, but attempts at generalization to many-electron polyatomic systems are frustrated by technical barriers. An alternative "quasi-classical" approach, which eliminates the explicit quantum dynamics of the electrons within a classical framework, yet retains the quantum character of the nuclear motion, appears capable of yielding EFDs for arbitrarily complex systems. Quasi-classical formulas for the EFD in simple systems agree with corresponding coupled-channels formulas. Results of the application of the new quasi-classical formula for the EFD to a model triatomic system indicate the potential of the quasi-classical scheme to elucidate the dynamical role of electrons in electronically adiabatic processes in more complex multiparticle systems.

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Concerted quantum effects of electronic and nuclear fluxes in molecules

Cited by 99 publications

References 39 publications

Quantum model simulations of attosecond electron diffraction

Quantum model simulations of attosecond electron diffraction

Nuclear velocity perturbation theory for vibrational circular dichroism: An approach based on the exact factorization of the electron-nuclear wave function

Quasi-Classical Theory of Electronic Flux Density in Electronically Adiabatic Molecular Processes

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