Water fragmentation by bare and dressed light ions with MeV energies: fragment-ion energy and velocity distributions

SHUCH, R.; TURCO, F.; SUARÉZ, S.; LUNA, H.; OTRANTO, S.; BERNARDI, G.; WOLFF, W.; CARIATORE, N. D.; FREGENAL, D.

PHYSICAL REVIEW A - ATOMIC, MOLECULAR AND OPTICAL PHYSICS

AMER PHYSICAL SOC

Lugar: New York; Año: 2016 vol. 94 p. 22712 - 2271211

1050-2947

The energy and time-of-flight distributions of water ionic fragments produced by impact of fast atoms and bareand dressed ions; namely, H+ , Li0?3+ , C1+ , and C2+ are reported in this work. Fragment species as a function ofemission energy and time-of-flight were recorded by using an electrostatic spectrometer and a time-of-flight massspectrometer, respectively. An improved Coulomb explosion model coupled to a classical trajectory Monte Carlo(CTMC) simulation gave the energy centroids of the fragments for the dissociation channels resulting from theremoval of two to five electrons from the water molecule. For the energy distribution ranging up to 50 eV, boththe experiment and model reveal an isotropic production of multiple charged oxygen ions, as well as hydrogenions. From the ion energy distribution, relative yields of the dissociation resulting from multiple ionization wereobtained as a function of the charge state, as well as for several projectile energies. Multiple-ionization yieldswith charge state up to 4+, were extracted from the measurements of the time-of-flight spectra, focused on theproduction of single and multiple charged oxygen ions. The measurements were compared to ion-water collisionexperiments investigated at the keV energy range available in the literature, revealing differences and similaritiesin the fragment-ion energy distribution.