scholarly journals Surface-response functions obtained from equilibrium electron-density profiles

Nanophotonics ◽  
2021 ◽  
Vol 0 (0) ◽  
Author(s):  
N. Asger Mortensen ◽  
P. A. D. Gonçalves ◽  
Fedor A. Shuklin ◽  
Joel D. Cox ◽  
Christos Tserkezis ◽  
...  
Keyword(s):  
Ab Initio ◽  
Electron Density ◽  
Response Functions ◽  
Model Calculations ◽  
Surface Response ◽  
Complementary Approach ◽  
Equilibrium Response ◽  
Electron Density Profiles ◽  
Spatially Varying ◽  
External Time

Abstract Surface-response functions are one of the most promising routes for bridging the gap between fully quantum-mechanical calculations and phenomenological models in quantum nanoplasmonics. Among all currently available recipes for obtaining such response functions, the use of ab initio methods remains one of the most conspicuous trends, wherein the surface-response functions are retrieved via the metal’s non-equilibrium response to an external time-dependent perturbation. Here, we present a complementary approach to approximate one of the most appealing surface-response functions, namely the Feibelman d-parameters, yield a finite contribution even when they are calculated solely with the equilibrium properties of the metal, described under the local-response approximation (LRA) but with a spatially varying equilibrium electron density, as input. Using model calculations that mimic both spill-in and spill-out of the equilibrium electron density, we show that the obtained d-parameters are in qualitative agreement with more elaborate, but also more computationally demanding, ab initio methods. The analytical work presented here illustrates how microscopic surface-response functions can emerge out of entirely local electrodynamic considerations.

Electron density profiles above the F-layer

1973 ◽  
Vol 21 (9) ◽  
pp. 1581-1586
Author(s):  
Michael Anastassiadis ◽  
Georges Moraitis ◽  
Dimitris Matsoukas
Keyword(s):  
Electron Density ◽  
Density Profiles ◽  
Electron Density Profiles

scholarly journals Ionospheric assimilation techniques for ARGOS Low-Resolution Airglow and Aurora Spectrograph (LORAAS) tomographically reconstructed equatorial electron density profiles

Radio Science ◽  
2004 ◽  
Vol 39 (1) ◽  
pp. n/a-n/a ◽  
Author(s):  
J. J. Sojka ◽  
J. V. Eccles ◽  
R. W. Schunk ◽  
S. McDonald ◽  
S. Thonnard ◽  
...  
Keyword(s):  
Electron Density ◽  
Low Resolution ◽  
Density Profiles ◽  
Electron Density Profiles

scholarly journals Ab initio response functions for Cherenkov-based neutron detectors

2018 ◽  
Vol 89 (10) ◽  
pp. 10I136 ◽  
Author(s):  
D. J. Schlossberg ◽  
A. S. Moore ◽  
B. V. Beeman ◽  
M. J. Eckart ◽  
G. P. Grim ◽  
...  
Keyword(s):  
Ab Initio ◽  
Response Functions ◽  
Neutron Detectors

scholarly journals σ2 R , a reciprocal-space measure of the quality of macromolecular electron-density maps

1999 ◽  
Vol 55 (6) ◽  
pp. 1174-1178 ◽  
Author(s):  
Thomas C. Terwilliger
Keyword(s):  
Standard Deviation ◽  
Ab Initio ◽  
Electron Density ◽  
Reciprocal Space ◽  
Rapid Evaluation ◽  
Reliable Measure ◽  
Similar Measure ◽  
Acta Cryst ◽  
Density Maps

It has previously been shown that the presence of distinct regions of solvent and protein in macromolecular crystals leads to a high value of the standard deviation of local r.m.s. electron density and that this can in turn be used as a reliable measure of the quality of macromolecular electron-density maps [Terwilliger & Berendzen (1999a). Acta Cryst. D55, 501–505]. Here, it is demonstrated that a similar measure, \sigma_{R}^{2}, the variance of the local roughness of the electron density, can be calculated in reciprocal space. The formulation is suitable for rapid evaluation of macromolecular crystallographic phases, for phase improvement and for ab initio phasing procedures.

scholarly journals Variations of topside ionospheric scale heights over Millstone Hill during the 30-day incoherent scatter radar experiment

2007 ◽  
Vol 25 (9) ◽  
pp. 2019-2027 ◽  
Author(s):  
L. Liu ◽  
W. Wan ◽  
M.-L. Zhang ◽  
B. Ning ◽  
S.-R. Zhang ◽  
...  
Keyword(s):  
Electron Density ◽  
Thermal Structure ◽  
Plasma Temperature ◽  
Scale Height ◽  
Incoherent Scatter Radar ◽  
Density Profiles ◽  
Incoherent Scatter ◽  
Scatter Radar ◽  
Vertical Scale ◽  
Electron Density Profiles

Abstract. A 30-day incoherent scatter radar (ISR) experiment was conducted at Millstone Hill (288.5° E, 42.6° N) from 4 October to 4 November 2002. The altitude profiles of electron density Ne, ion and electron temperature (Ti and Te), and line-of-sight velocity during this experiment were processed to deduce the topside plasma scale height Hp, vertical scale height VSH, Chapman scale height Hm, ion velocity, and the relative altitude gradient of plasma temperature (dTp/dh)/Tp, as well as the F2 layer electron density (NmF2) and height (hmF2). These data are analyzed to explore the variations of the ionosphere over Millstone Hill under geomagnetically quiet and disturbed conditions. Results show that ionospheric parameters generally follow their median behavior under geomagnetically quiet conditions, while the main feature of the scale heights, as well as other parameters, deviated significantly from their median behaviors under disturbed conditions. The enhanced variability of ionospheric scale heights during the storm-times suggests that the geomagnetic activity has a major impact on the behavior of ionospheric scale heights, as well as the shape of the topside electron density profiles. Over Millstone Hill, the diurnal behaviors of the median VSH and Hm are very similar to each other and are not so tightly correlated with that of the plasma scale height Hp or the plasma temperature. The present study confirms the sensitivity of the ionospheric scale heights over Millstone Hill to thermal structure and dynamics. The values of VSH/Hp tend to decrease as (dTp/dh)/Tp becomes larger or the dynamic processes become enhanced.

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