Isotope effects in dynamics of water isotopologues induced by core ionization at an x-ray free-electron laser

R Guillemin; L Inhester; M Ilchen; T Mazza; R Boll; Th Weber; S Eckart; P Grychtol; N Rennhack; T Marchenko; N Velasquez; O Travnikova; I Ismail; J Niskanen; E Kukk; F Trinter; M Gisselbrecht; R Feifel; G Sansone; D Rolles; M Martins; M Meyer; M Simon; R Santra; T Pfeifer; T Jahnke; M N Piancastelli

doi:10.1063/4.0000197

Isotope effects in dynamics of water isotopologues induced by core ionization at an x-ray free-electron laser

Struct Dyn. 2023 Oct 3;10(5):054302. doi: 10.1063/4.0000197. eCollection 2023 Sep.

Authors

R Guillemin¹, L Inhester², M Ilchen, T Mazza³, R Boll³, Th Weber⁴, S Eckart⁵, P Grychtol³, N Rennhack³, T Marchenko¹, N Velasquez¹, O Travnikova¹, I Ismail¹, J Niskanen⁶, E Kukk⁶, F Trinter, M Gisselbrecht⁷, R Feifel⁸, G Sansone⁹, D Rolles¹⁰, M Martins¹¹, M Meyer³, M Simon¹, R Santra, T Pfeifer¹², T Jahnke¹², M N Piancastelli¹

Affiliations

¹ Sorbonne Université, CNRS, Laboratoire de Chimie Physique-Matière et Rayonnement, LCPMR, 75005 Paris, France.
² Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.
³ European XFEL, 22869 Schenefeld, Germany.
⁴ Lawrence Berkeley National Laboratory, Chemical Sciences, Berkeley, California 94720, USA.
⁵ Institut für Kernphysik, Goethe-Universität, 60438 Frankfurt am Main, Germany.
⁶ Department of Physics and Astronomy, University of Turku, 20014 Turku, Finland.
⁷ Department of Physics, Lund University, 22100 Lund, Sweden.
⁸ Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden.
⁹ Physikalisches Institut, Universität Freiburg, 79104 Freiburg, Germany.
¹⁰ J. R. Macdonald Laboratory, Department of Physics, Kansas State University, Manhattan, Kansas 66506, USA.
¹¹ Institut für Experimentalphysik, Universität Hamburg, 22761 Hamburg, Germany.
¹² Max-Planck-Institut für Kernphysik, 69117 Heidelberg, Germany.

Abstract

Dynamical response of water exposed to x-rays is of utmost importance in a wealth of science areas. We exposed isolated water isotopologues to short x-ray pulses from a free-electron laser and detected momenta of all produced ions in coincidence. By combining experimental results and theoretical modeling, we identify significant structural dynamics with characteristic isotope effects in H₂O²⁺, D₂O²⁺, and HDO²⁺, such as asymmetric bond elongation and bond-angle opening, leading to two-body or three-body fragmentation on a timescale of a few femtoseconds. A method to disentangle the sequences of events taking place upon the consecutive absorption of two x-ray photons is described. The obtained deep look into structural properties and dynamics of dissociating water isotopologues provides essential insights into the underlying mechanisms.