Hamburg 2009 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 32: Attosecond Physics III
A 32.2: Fachvortrag
Donnerstag, 5. März 2009, 17:00–17:30, VMP 6 HS-E
Anomalous quasi-elastic electron scattering and neutron Compton scattering from single nuclei of H2, D2 and HD molecules — C. Aris C.-Dreismann1, Glyn Cooper2, and •Adam P. Hitchcock2 — 1Institute of Chemistry, Technical University of Berlin, D-10623 Berlin — 2Brockhouse Institute for Materials Research, McMaster University, Hamilton, ON, Canada L8S 4M1
Quasi-elastic electron scattering from gaseous H2, D2, a 50:50 mixture of H2 and D2 and HD is investigated with 2.25 keV impact energy, at a momentum transfer q of 19.7 a.u. [1]. The spectral positions of the H and D recoil peaks follow Rutherford scattering theory. Surprisingly, in the spectrum of the 50:50 H2-D2 mixture, the integrated intensity of the H peak is about 30 percent lower (as compared to that of D) than predicted by Rutherford scattering, despite equal screening of nuclear charges by the electrons in all molecules. In contrast, the ratio of scattering intensities from HD agrees with the predictions of Rutherford scattering. This result was recently confirmed with a second experiment (M. Vos, ANU) applyiing 6 keV electrons. Comparison is made with neutron Compton scattering (NCS) results, which showed the same anomaly in H2-D2 and HD (about 30 percent in both systems). This anomalous effect is proposed to be due to attosecond scattering dynamics from entangled particles, and can be understood with the aid of the Quantum Zeno Effect.
[1] G. Cooper, A. P. Hitchcock, C. A. Chatzidimitriou-Dreismann, PRL 100, 043204 (2008)