Isotope effects in dynamics of water isotopologues induced by core ionization at an x-ray free-electron laser.
Renaud GuilleminLudger InhesterMarkus IlchenT MazzaRebecca BollThorsten WeberSebastian EckartPatrik GrychtolNils RennhackTatiana MarchenkoN VelasquezO TravnikovaIyas IsmailJohannes NiskanenEdwin KukkFlorian TrinterMathieu GisselbrechtRaimund FeifelGiuseppe SansoneDaniel RollesMichael MartinsMichael MeyerMarc SimonRobin SantraThomas PfeiferTill JahnkeMaria Novella PiancastelliPublished in: Structural dynamics (Melville, N.Y.) (2023)
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 H 2 O 2+ , D 2 O 2+ , and HDO 2+ , 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.