Semiclassical Theory of Dechanneling and the Diffusion Coefficients

Abstract

A new expression of the "local diffusion coefficient" for dechanneling theory is derived within a framework of the semiclassical approximation. By making use of the present result, the diffusion coefficient for nuclear contribution is calculated in detail. It is shown that the nuclear diffusion coefficient can be approximately represented in the form D,= Dg -O+ DL where Dg-0 and DL are the Kitagawa-Ohtsuki's formula and the Lindhard's formula, respectively. These conclusions correspond to Matsunami-Howe's proposal and Fuschini-Uguzzoni's computer simulation. Im Rahmen einer halbklassischen Niiherung wird ein neuer Ausdruck des , ,lokalen Diffusionskoeffizienten" fur die Dekanalisierungstheorie abgeleitet. Unter Benutzung dieses Ergebnisses wird der Diffusionskoeffizient fur den Kernanteil ausfuhrlich berechnet. Es wird gezeigt, da13 der Kerndiffusionskoeffizient niiherungsweise in der Form D, = D K -0 + DL dargestellt werden kann, wo DK-0 und DL die Kitagawa-Ohtsuki bzw. die Lindhard-Formeln sind. Diese Ergebnisse stimmen mit den Vorhersagen von Matsunami-Howe und der Computersimulation von Fuschini-Uguzzoni uberein.

Diffusion model of dechanneling based on the Boltzmann equation: Three regimes of energetic particle motion in crystals

“…However, the coefficients which are derived on the basis of local kinetic equations [5, 12,17 to 201 have only a limited interest since all proofs of these equations contain rough approximations. In [23] the author developed a more consistent derivation on using the Schrodinger equation. The main attention was devoted to analyzing the equation for the Wigner distribution function, as a result, the definition of the local diffusion coefficient [23] deviates from previous ones [l, 17, 191.…”

“…In [23] the author developed a more consistent derivation on using the Schrodinger equation. The main attention was devoted to analyzing the equation for the Wigner distribution function, as a result, the definition of the local diffusion coefficient [23] deviates from previous ones [l, 17, 191. One has been forced back to see whether one could derive the local kinetic equation from a more fundamental point of view.…”