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Free electron model
About: Free electron model is a research topic. Over the lifetime, 4678 publications have been published within this topic receiving 103535 citations.
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TL;DR: In this paper, the detailed energy band structures of hexagonal beryllium and magnesium have been computed by the composite-wave variational method in conjunction with the quantum defect method.
Abstract: The detailed energy band structures of hexagonal beryllium and magnesium have been computed by the composite-wave variational method in conjunction with the quantum defect method. From these energy band data, the density of states and Fermi surface of both these metals have been worked out and compared with the experimental and theoretical results of other workers. The results show a marked deviation of the energy bands of Be from the free electron behaviour, that for Mg being small. The Fermi surface of Be consists of a monster and two identical cigars, while that of Mg, following more or less the free electron nature, consists of several pieces in the form of a monster, cigars, lens, pockets and butterfly. These are found to agree favourably with experimental results.
25 citations
TL;DR: In this paper, the authors study the nanoscale features of spontaneous and stimulated electron-photon interactions mediated by localized surface plasmon resonances at the tips of a gold nanostar using electron energy-loss spectroscopy (EELS), cathodoluminescence spectrograms (CL), and photon-induced near-field electron microscopy (PINEM).
Abstract: The interplay between free electrons, light, and matter offers unique prospects for space, time, and energy resolved optical material characterization, structured light generation, and quantum information processing. Here, we study the nanoscale features of spontaneous and stimulated electron–photon interactions mediated by localized surface plasmon resonances at the tips of a gold nanostar using electron energy-loss spectroscopy (EELS), cathodoluminescence spectroscopy (CL), and photon-induced near-field electron microscopy (PINEM). Supported by numerical electromagnetic boundary-element method (BEM) calculations, we show that the different coupling mechanisms probed by EELS, CL, and PINEM feature the same spatial dependence on the electric field distribution of the tip modes. However, the electron–photon interaction strength is found to vary with the incident electron velocity, as determined by the spatial Fourier transform of the electric near-field component parallel to the electron trajectory. For the tightly confined plasmonic tip resonances, our calculations suggest an optimum coupling velocity at electron energies as low as a few keV. Our results are discussed in the context of more complex geometries supporting multiple modes with spatial and spectral overlap. We provide fundamental insights into spontaneous and stimulated electron-light-matter interactions with key implications for research on (quantum) coherent optical phenomena at the nanoscale.
25 citations
TL;DR: Nisoli et al. as mentioned in this paper proposed a non-perturbative approach based on Coulomb-Volkov states to predict ionisation of atoms by intense laser pulses in cases where the effective interaction time does not exceed one or two optical cycles.
Abstract: A simple theoretical approach based on Coulomb-Volkov states is introduced to predict ionisation of atoms by intense laser pulses in cases where the effective interaction time does not exceed one or two optical cycles [M. Nisoli et al., Opt. Lett. 22, 522 (1997)]. Under these conditions, the energy distributions of ejected electrons predicted by this non-perturbative approach are in very good agreement with “exact" results obtained by a full numerical treatment. The agreement is all the better that the principal quantum number of the initial state is high. For very strong fields, most electrons are ejected at an energy which is close to the classical kinetic energy that would be transferred to free electrons by the electromagnetic field during the pulse. The power of the present approach appears when keV. In this region, full numerical treatments become very lengthy and finally do not converge. However, the present Coulomb-Volkov theory still makes reliable predictions in very short computer times.
25 citations
TL;DR: In this paper, a self-consistent joint description of free and weakly bound electron states in plasmas is considered and the existence of two problems is emphasized: restriction of the number of atomic excited states and description of the smooth crossover from bound pair electron-ion excited states to collective excitations of tree electrons.
Abstract: Self-consistent Joint description of free and weakly bound electron states in plasmas is considered. Existence of two problems is emphasized: restriction of the number of atomic excited states and description of the smooth crossover from bound pair electron-ion excited states to collective excitations of tree electrons. The spectrum domain intermediate between low-lying excited atoms and free electron continuous energy levels is Studied. Density and nonideality effects arc separated. The density effects are predominant for the shape of the curve of the energy spectrum near the ionization limit. It corresponds to the Suppression of spectral lines in ideal multi-charge plasma of warm dense matter. A Suppression of collisional recombination turns Out to be a nonideality effects. The suppression agrees with the measurements for ultracold plasmas and Warm dense matter. (C) 2009 WILEY-VCH Verlag GmbH & Co. KGaA. Weinehim
25 citations
TL;DR: A new model for free electrons in water suggests that they are localized in regions of enhanced rather than depleted water density, and not only penetrates the charge distribution of the water molecules but also is associated with a region of enhanced water density rather than a cavity.
Abstract: A new model for free electrons in water suggests that they are localized in regions of enhanced rather than depleted water density.
25 citations