Anomalously strong two-electron one-photon X-ray decay transitions in CO caused by avoided crossing.

Rafael C Couto, Marco Guarise, Alessandro Nicolaou, Nicolas Jaouen, Gheorghe S Chiuzbăian, Jan Lüning, Victor Ekholm, Jan-Erik Rubensson, Conny Såthe, Franz Hennies, Victor Kimberg, Freddy F Guimarães, Hans Agren, Faris Gel'mukhanov, Loïc Journel, Marc Simon

Research output: Contribution to journalArticlepeer-review


The unique opportunity to study and control electron-nuclear quantum dynamics in coupled potentials offered by the resonant inelastic X-ray scattering (RIXS) technique is utilized to unravel an anomalously strong two-electron one-photon transition from core-excited to Rydberg final states in the CO molecule. High-resolution RIXS measurements of CO in the energy region of 12-14 eV are presented and analyzed by means of quantum simulations using the wave packet propagation formalism and ab initio calculations of potential energy curves and transition dipole moments. The very good overall agreement between the experimental results and the theoretical predictions allows an in-depth interpretation of the salient spectral features in terms of Coulomb mixing of "dark" with "bright" final states leading to an effective two-electron one-photon transition. The present work illustrates that the improved spectral resolution of RIXS spectra achievable today may call for more advanced theories than what has been used in the past.
Original languageEnglish
Article number20947
JournalScientific Reports
Publication statusPublished - 2016

Subject classification (UKÄ)

  • Physical Chemistry


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