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1. Parametric dependence of hot electron relaxation timescales on electron-electron and electron-phonon interaction strengths

   https://doi.org/10.1038/s42005-020-00442-x  

   Wilson, Richard B.; Coh, Sinisa (December 2020, Communications Physics)

   null (Ed.)

   Abstract Understanding how photoexcited electron dynamics depend on electron-electron (e-e) and electron-phonon (e-p) interaction strengths is important for many fields, e.g. ultrafast magnetism, photocatalysis, plasmonics, and others. Here, we report simple expressions that capture the interplay of e-e and e-p interactions on electron distribution relaxation times. We observe a dependence of the dynamics on e-e and e-p interaction strengths that is universal to most metals and is also counterintuitive. While only e-p interactions reduce the total energy stored by excited electrons, the time for energy to leave the electronic subsystem also depends on e-e interaction strengths because e-e interactions increase the number of electrons emitting phonons. The effect of e-e interactions on energy-relaxation is largest in metals with strong e-p interactions. Finally, the time high energy electron states remain occupied depends only on the strength of e-e interactions, even if e-p scattering rates are much greater than e-e scattering rates. 

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2. Electron spectra for twisted electron collisions

   https://doi.org/10.1088/1361-6455/ac41b1  

   Plumadore, A; Harris, A L (December 2021, Journal of Physics B: Atomic, Molecular and Optical Physics)

   Abstract Ionization collisions have important consequences in many physical phenomena, and the mechanism that leads to ionization is not universal. Double differential cross sections (DDCSs) are often used to identify ionization mechanisms because they exhibit features that distinguish close collisions from grazing collisions. In the angular DDCS, a sharp peak indicates ionization through a close binary collision, while a broad angular distribution points to a grazing collision. In the DDCS energy spectrum, electrons ejected through a binary encounter collision result in a peak at an energy predicted from momentum conservation. These insights into ionization processes are well-established for plane wave projectiles. However, the recent development of sculpted particle wave packets reopens the question of how ionization occurs for these new particle wave forms. We present theoretical DDCSs for (e, 2e) ionization of atomic hydrogen for electron vortex projectiles. Our results predict that the ionization mechanism for vortex projectiles is similar to that of non-vortex projectiles, but that the projectile’s momentum uncertainty causes noticeable changes to the shape and magnitude of the vortex DDCSs. Specifically, there is a broadening and splitting of the angular DDCS peak for vortex projectiles, and an increase in the cross section for high energy ejected electrons. 

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3. Electron-Photon Interactions in a Scanning Electron Microscope

   https://doi.org/10.1109/IVNC57695.2023.10188999  

   Simonaitis, John W.; Krielaart, Maurice A.; Koppell, Stewart A.; Slayton, Benjamin J.; Alongi, Joseph; Putnam, William P.; Berggren, Karl K.; Keathley, Phillip D. (July 2023, 2023 IEEE 36th International Vacuum Nanoelectronics Conference (IVNC))
4. Electron-electron interactions and high-order harmonics in solids

   https://doi.org/10.1103/PhysRevB.106.235124  

   Alam, Didarul; Ud Din, Naseem; Chini, Michael; Turkowski, Volodymyr (December 2022, Physical Review B)
5. A simple one-electron expression for electron rotational factors

   https://doi.org/10.1063/5.0192083  

   Qiu, Tian; Bhati, Mansi; Tao, Zhen; Bian, Xuezhi; Rawlinson, Jonathan; Littlejohn, Robert G; Subotnik, Joseph E (March 2024, The Journal of Chemical Physics)

   Within the context of fewest-switch surface hopping (FSSH) dynamics, one often wishes to remove the angular component of the derivative coupling between states J and K. In a previous set of papers, Shu et al. [J. Phys. Chem. Lett. 11, 1135–1140 (2020)] posited one approach for such a removal based on direct projection, while we isolated a second approach by constructing and differentiating a rotationally invariant basis. Unfortunately, neither approach was able to demonstrate a one-electron operatorÔ whose matrix element JÔK was the angular component of the derivative coupling. Here, we show that a one-electron operator can, in fact, be constructed efficiently in a semi-local fashion. The present results yield physical insight into designing new surface hopping algorithms and are of immediate use for FSSH calculations. 

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