scholarly journals Alternative treatment for the energy-transfer and transport cross section in dressed electron-ion binary collisions

2016 ◽  
Vol 94 (4) ◽  
Author(s):  
P. L. Grande
Author(s):  
R.D. Leapman ◽  
P. Rez ◽  
D.F. Mayers

Microanalysis by EELS has been developing rapidly and though the general form of the spectrum is now understood there is a need to put the technique on a more quantitative basis (1,2). Certain aspects important for microanalysis include: (i) accurate determination of the partial cross sections, σx(α,ΔE) for core excitation when scattering lies inside collection angle a and energy range ΔE above the edge, (ii) behavior of the background intensity due to excitation of less strongly bound electrons, necessary for extrapolation beneath the signal of interest, (iii) departures from the simple hydrogenic K-edge seen in L and M losses, effecting σx and complicating microanalysis. Such problems might be approached empirically but here we describe how computation can elucidate the spectrum shape.The inelastic cross section differential with respect to energy transfer E and momentum transfer q for electrons of energy E0 and velocity v can be written as


1973 ◽  
Vol 34 (4) ◽  
pp. 372-373
Author(s):  
I. K. Kalugina ◽  
I. B. Keirim-Markus ◽  
A. K. Savinskii ◽  
I. V. Filyushkin

2003 ◽  
Vol 125 (6) ◽  
pp. 1156-1162 ◽  
Author(s):  
Ravi Prasher

Equation of phonon radiative transport (EPRT) is rewritten to include anisotropic scattering by a particulate media by including an acoustic phase function and an inscattering term which makes EPRT exactly same as equation of radiative transport (ERT). This formulation of EPRT is called generalized EPRT (GEPRT). It is shown that GEPRT reduces to EPRT for isotropic scattering and is totally consistent with phonon transport theory, showing that transport cross section is different from the scattering cross section. GEPRT leads to same formulation for transport cross section as given by phonon transport theory. However GEPRT shows that transport cross section formulations as described by phonon transport theory are only valid for acoustically thick medium. Transport cross section is different for the acoustically thin medium leading to the conclusion that mean free path (m.f.p) is size dependant. Finally calculations are performed for two types of scatterers for acoustic waves without mode conversion: (1) acoustically hard Rayleigh sphere; and (2) large sphere in the geometrical scattering regime. Results show that the scattering from these particles is highly anisotropic. It is also shown that for geometrical scattering case isotropic scattering leads to the conclusion of total internal reflection at the particle/medium interface.


1996 ◽  
Vol 104 (22) ◽  
pp. 9001-9015 ◽  
Author(s):  
Liu Ming ◽  
Jan Davidsson ◽  
Sture Nordholm

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