ausblenden:
Schlagwörter:
quantum reflection; helium dimer; helium trimer; matter-wave diffraction;
blazed diffraction grating
Zusammenfassung:
We report on non-destructive scattering and diffraction of He, He2, and He3 from a plane ruled
reflection grating. At grazing incidence the normal component of the particle’s wave-vector
is sufficiently small to allow for quantum reflection at the attractive Casimir-van der Waals
particle–surface interaction potential. Quantum reflection occurs tens of nanometers in front
of the surface, before the dimers and trimers reach the region where the surface-induced forces
would inevitably cause breakup of the fragile bonds. The reflected particles are identified via
their mass-dependent diffraction angles and by mass spectrometry. The intensity distributions
of the observed diffraction patterns are discussed in terms of the grating’s blaze angle.
