scholarly journals Electron and nuclear dynamics following ionisation of modified bismethylene-adamantane

2016 ◽  
Vol 194 ◽  
pp. 95-115 ◽  
Author(s):  
Morgane Vacher ◽  
Fabio E. A. Albertani ◽  
Andrew J. Jenkins ◽  
Iakov Polyak ◽  
Michael J. Bearpark ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Wave Packet ◽  
Half Life ◽  
Electronic States ◽  
Nuclear Motion ◽  
Hole Density ◽  
Electron Dynamics ◽  
Nuclear Dynamics ◽  
Bond Lengths ◽  
Methylene Groups

We have simulated the coupled electron and nuclear dynamics using the Ehrenfest method upon valence ionisation of modified bismethylene-adamantane (BMA) molecules where there is an electron transfer between the two π bonds. We have shown that the nuclear motion significantly affects the electron dynamics after a few fs when the electronic states involved are close in energy. We have also demonstrated how the non-stationary electronic wave packet determines the nuclear motion, more precisely the asymmetric stretching of the two π bonds, illustrating “charge-directed reactivity”. Taking into account the nuclear wave packet width results in the dephasing of electron dynamics with a half-life of 8 fs; this eventually leads to the equal delocalisation of the hole density over the two methylene groups and thus symmetric bond lengths.

scholarly journals Control of nuclear dynamics in the benzene cation by electronic wavepacket composition

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Thierry Tran ◽  
Graham A. Worth ◽  
Michael A. Robb
Keyword(s):  
Extreme Ultraviolet ◽  
Initial Conditions ◽  
Chemical Reactivity ◽  
Electronic States ◽  
Time Dependent ◽  
Electronic Control ◽  
Electron Dynamics ◽  
Nuclear Dynamics ◽  
Successive Passage ◽  
Dynamics Simulations

AbstractThe study of coupled electron-nuclear dynamics driven by coherent superpositions of electronic states is now possible in attosecond science experiments. The objective is to understand the electronic control of chemical reactivity. In this work we report coherent 8-state non-adiabatic electron-nuclear dynamics simulations of the benzene radical cation. The computations were inspired by the extreme ultraviolet (XUV) experimental results in which all 8 electronic states were prepared with significant population. Our objective was to study the nuclear dynamics using various bespoke coherent electronic state superpositions as initial conditions in the Quantum-Ehrenfest method. The original XUV measurements were supported by Multi-configuration time-dependent Hartree (MCTDH) simulations, which suggested a model of successive passage through conical intersections. The present computations support a complementary model where non-adiabatic events are seen far from a conical intersection and are controlled by electron dynamics involving non-adjacent adiabatic states. It proves to be possible to identify two superpositions that can be linked with two possible fragmentation paths.

scholarly journals Electron–Nuclear Dynamics Accompanying Proton-Coupled Electron Transfer

2021 ◽  
Vol 143 (8) ◽  
pp. 3104-3112
Author(s):  
Yusuke Yoneda ◽  
S. Jimena Mora ◽  
James Shee ◽  
Brian L. Wadsworth ◽  
Eric A. Arsenault ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Nuclear Dynamics ◽  
Proton Coupled Electron Transfer

scholarly journals Analytical Theory of Attosecond Transient Absorption Spectroscopy of Perturbatively Dressed Systems

2019 ◽  
Vol 9 (7) ◽  
pp. 1350
Author(s):  
Daria Kolbasova ◽  
Robin Santra
Keyword(s):  
Perturbation Theory ◽  
Absorption Spectroscopy ◽  
Transient Absorption ◽  
Electronic States ◽  
Theoretical Description ◽  
Transient Absorption Spectroscopy ◽  
Electron Dynamics ◽  
Optical Pulses ◽  
Absorption Signal ◽  
Level Model

A theoretical description of attosecond transient absorption spectroscopy for temporally and spatially overlapping XUV and optical pulses is developed, explaining the signals one can obtain in such an experiment. To this end, we employ a two-stage approach based on perturbation theory, which allows us to give an analytical expression for the transient absorption signal. We focus on the situation in which the attosecond XUV pulse is used to create a coherent superposition of electronic states. As we explain, the resulting dynamics can be detected in the spectrum of the transmitted XUV pulse by manipulating the electronic wave packet using a carrier-envelope-phase-stabilized optical dressing pulse. In addition to coherent electron dynamics triggered by the attosecond pulse, the transmitted XUV spectrum encodes information on electronic states made accessible by the optical dressing pulse. We illustrate these concepts through calculations performed for a few-level model.

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