Two-Center Interference in p-H2 Electron-Transfer Collisions

We report on measurements of transfer excitation in collisions of 0.3-1.3 MeV protons with spatially oriented H2 molecules. Evidences of two center interference are found in the angular distribution of the molecule after a transfer excitation process and directly in the projectile angular scattering distributions. These features can be explained in a way which is analogous to that for the interferences in Young\u27s classical double slit experiment: The fast projectiles preferentially capture electrons close to either of the molecular nuclei, and thereby they change their momenta and de Broglie wavelengths. The waves emerging from the two \u27slits\u27 of the molecule interfere yielding the observed interference structure

Evidence of Wave-Particle Duality for Single Fast Hydrogen Atoms

We report the direct observation of interference effects in a Young\u27s double-slit experiment where the interfering waves are two spatially separated components of the de Broglie wave of single 1.3 MeV hydrogen atoms formed close to either target nucleus in H++H2 electron-transfer collisions. Quantum interference strongly influences the results even though the hydrogen atoms have a de Broglie wavelength, λdB, as small as 25 fm

Experimental Separation of the Thomas Charge-Transfer Process in High-Velocity p-He Collisions

We present differential cross sections of electron capture in 7.5 MeV and 12.5 MeV proton-helium collisions. Complete experimental separations of the Thomas and the kinematic single electron capture processes in the two-dimensional He+ momentum distribution in the plane perpendicular to the fast ion beam have been achieved. We compare the resulting projectile angular differential cross section with the two most recent theoretical calculations and expose significant deviations

Importance of Thomas Single-Electron Transfer in Fast p-He Collisions

We report experimental angular differential cross sections for nonradiative single-electron capture in p-He collisions (p+ He → H + He+) with a separate peak at the 0.47 mrad Thomas scattering angle for energies in the 1.3-12.5 MeV range. We find that the intensity of this peak scales with the projectile velocity as vP-11. This constitutes the first experimental test of the prediction from 1927 by L. H. Thomas [Proc. R. Soc. 114, 561 (1927)]. At our highest energy, the peak at the Thomas angle contributes with 13.5% to the total integrated nonradiative single-electron capture cross section

Angular Scattering in Fast Ion-Atom Electron Transfer Collisions: Projectile Wave Diffraction and Thomas Mechanisms

We report experimental angular differential cross sections for double-electron capture in He2+ + He collisions and single-electron capture in H+ + He collisions for the 1.3-12.5 MeV kinetic energy range. In all cases, the total cross sections are dominated by forward scattering peaks in dσ/dΩ. The shapes and widths (but not the magnitudes) of these peaks are very similar for all energies and for capture of one or two electrons corresponding also to our measured linear increases in the transverse momentum transfers with increasing projectile velocities. These observations may be ascribed to diffraction limitations which are connected to electron transfer probabilities P(b) which are significant in limited regions of b only. For the H+ + He single-electron capture we observe two additional maxima in the angular differential cross sections. We conclude that while the secondary maxima at ~0.5 mrad probably have large contributions from the Thomas proton-electron-nucleus scattering mechanism, the third maxima at ~0.75 mrad are most likely mainly due to projectile de Broglie wave diffraction