Coherent control of nonradiative electron capture in electron-ion collisions: Exploiting Heisenberg's Uncertainty Principle and the projectile beam coherence.

The capture of an electron by a positively charged ion accompanied by photoemission is a well-established mechanism for radiative recombination in electron-ion collisions: the emitted photons take away the excess energy necessary for electron capture or stabilization. We propose a non-radiative mechanism by which the momentum transferred by the incident electron to the center-of-mass of the target ion results in a recoil of the latter, which then provides the necessary outflow of energy to ensure energy conservation and achieve nonradiative recombination. Motivated by recent experimental advances in tailoring photoelectron wave packets in ultrafast multiphoton ionization [1] as well as the observation of fingerprints of the projectile’s coherence in angle-resolved cross-section measurements [2] , we exploit this mechanism and propose a coherent and selective control scheme over competing collisional reaction channels based on the initial preparation of the projectile electron wave packet. We demonstrate that the coherence and relative phase velocity of amplitude-modulated free-electron wave packets generated in interfering multiphoton ionization channels, together with the position-momentum uncertainty associated with the center-of-mass of the target ion, can be exploited to induce quantum interferences among energetically degenerate asymptotic configuration channels, thereby achieving selective control over the collision outcome.

[1] Kerbstadt et al., Advances in Physics: X 4 (2019) 1672583.

[2] Egodapitiya et al. Rev. Lett. 106 (2011) 153202.