Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 12: Postersitzung (Struktur und Dynamik reiner Oberfl
ächen, Grenzfl
äche fest-flüssig, Nanostrukturen, Teilchen und Cluster, Halbleiteroberfl
ächen und Grenzfl
ächen, Zeitaufgelöste Spektroskopie, Rastersondentechniken, Methodisches)

O 12.2: Poster

Montag, 24. März 2003, 18:00–21:00, P1

High Energy Quantum Reflection as a New Method for Surface Science — •Viola Druzhinina and Maarten DeKieviet — Physikalisches Institut, Universität Heidelberg, Phylosophenweg 12, D-69120 Heidelberg

Too large acceleration of a very slow neutral atom into an attractive atom-surface potential leads to specular reflection long before the atom reaches the repulsive wall. This pure quantum-mechanical phenomenon becomes more prominent for lower primary velocity of the atom normal to the surface. A key feature of quantum reflection (QR) is that the smaller the primary kinetic energy, the further away from the surface the atom is reflected. By measurement the QR coefficient as a function of the primary kinetic energy it is possible to probe the potential exactly [1]. From a Surface Science point of view, it is also interesting to study QR in the No-dqhigh energyNo-dq limit, since the surface structure then plays an importent role [2].

Here, we present experimental data on QR of neutral 3He atoms from both an atomically disorded Au(111)and a nanoscopically stepped α-quartz surface. The dependence of the QR coefficient on the details of the surface topology is modelled. The experimental results are in a very good agreement with the theoretical predictions [3].

[1] F. Shimizu, PRL 86, 987 (2001)

[2] V. Druzhinina and M. DeKieviet, http://lanl.arxiv.org/abs/quant-ph/0212076

[3] H. Friedrich, G. Jacoby and C. G. Meister, PR A 65, 032902 (2002)

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