Regensburg 2025 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 15: Poster Session I

CPP 15.33: Poster

Monday, March 17, 2025, 19:00–21:00, P4

Analysis of the Reciprocity Theorem in the DWBA — •Reinhard Sigel — Independent Scientist, D-88677 Markdorf, Germany

The Distorted Wave Born Approximation (DWBA) is a favored theory among X-ray scientists for the analysis of interface scattering experiments [1,2]. Unfortunately, there is no proper clarification which X-ray specific aspects and approximations enter the DWBA and what is the difference to interface scattering of coherent visible laser light. Based on the differing refractive index approaches for X-rays and for visible light, we identify the spot where an X-ray specific equation enters the derivation [1] of the so-called reciprocity theorem. It involves an intermixing of microscopic and macroscopic Maxwell equations. A much simpler correct derivation valid for both wavelength ranges is discussed.

[1] Daillant, Gibaud, X-ray and Neutron Reflectivity, Springer 2009.

[2] Renaud, Lazzari, Leroy, Surf. Sci. Reports 64, 255–380 (2009).

Keywords: Distorted Wave Born Approximation (DWBA); reciprocity theorem; interface scattering; diople density; macroscopic Maxwell equations