Localization and loss of coherence in molecular double-slit experiments

Abstract

In molecular double-slit experiments, the interference between emitted core electrons of diatomic molecules gives rise to oscillations in the observed electron intensity. Here, we explore this behaviour for photoelectrons emitted from CO and N2 by soft X-ray ionization in the molecular frame, and we argue that in addition to the undisturbed emission process, intramolecular scattering can lead to electron interference between the scattered and unscattered wave in two ways: two-centre interference between two spatially coherent emitters and one-centre self-interference. The latter is the signature of a loss of spatial coherence. The spatial scale over which the transition from two-centre to one-centre coherence occurs is the de Broglie wavelength of the scattered photoelectron in units of the bond length. These results highlight the fact that the molecular double slit is based on two independent uncertainty principles, ΔpxΔx and ΔEΔt, the second of which causes ongoing tunnelling between the two centres, even after the collapse of the electron wavefunction in real space. Similar to electrons passed through a double-slit apparatus, photoelectrons emitted coherently from both atoms of a diatomic molecule can exhibit interference patterns. But when coherence between the two atoms is lost, effects are shown to come into play that are unique to the ‘molecular double-slit’ experiment.

Cite this article

Zimmermann, B., Rolles, D., Langer, B. et al. Localization and loss of coherence in molecular double-slit experiments. Nature Phys 4, 649–655 (2008). https://doi.org/10.1038/nphys993

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