A comparison of Fraunhofer-type diffraction from an atomic single-slit and a molecular double-slit

TL;DR

This study compares the diffraction patterns from atomic and molecular slits in electron capture collisions, revealing differences in interference patterns for various electronic states and developing a model to interpret the scattering impact.

Contribution

It introduces a novel toy model for reaction impact-parameter dependence and demonstrates the molecular double-slit diffraction analogy in electron capture processes.

Findings

H2+ acts as a molecular double-slit in scattering.

Equal fringe width for single and double slit in ground state capture.

Different diffraction patterns observed for excited state capture.

Abstract

We measured the Q-value and the scattering angle distributions for non-dissociative state selective single electron capture in collisions of 7.5 keV H$^+$ and 15 keV H$_2^+$ with He. The experimental data are compared with semiclassical close-coupling calculations and predictions from the classical trajectory Monte Carlo simulations. By analogy with Fraunhofer diffraction, we also developed a toy model to reconstruct an imaginary screen that reflects the reaction impact-parameter dependence, in channels where the magnetic quantum number remains unchanged. It is well established that H$_2^+$ acts as a molecular double-slit in scattering processes. By demodulating the Young's double-slit-type interference pattern, we extracted the individual slit diffraction pattern of H$_2^+$ and compared it with that of the H$^+$ atomic single-slit. For ground state electron capture, we found that the single and the double slit diffraction patterns have equal fringe width, whereas for excited state electron capture, diffraction patterns are quite different.