Dissociative ionization of H₂by fast protons: three-body break-up and molecular-frame electron emission

Abstract

Highly differential cross sections have been obtained for dissociative single ionization of H 2 by 6MeV proton impact by measuring the momentum vectors of the electron and the H + fragment in coincidence. The investigation of the momentum balance of the fragments along the projectile beam provided detailed insight into the four-particle dynamics, even though the H atom is not detected. Within the axial recoil approximation, first molecular-frame angular distributions of emitted electrons have been determined for molecules oriented perpendicular to the projectile beam. They are compared to the predictions of a CDW-EIS calculation.

Coherent electron emission from simple molecules by impact of energetic charged particles

“…[59]). Highly differential cross sections for dissociative single ionization of H 2 molecules by 6 MeV proton impact have been measured using COLTRIMS [60]. The few-particle dynamics is fully determined from the momentum balance of all the fragments and, within the axial recoil approximation, molecular-frame angular distributions of the emitted electrons have been determined for molecules oriented perpendicular to the projectile beam.…”

Fivefold differential cross sections for ground-state ionization of aligned H2 by electron impact

“…Recently, efforts have been made to combine this method with ion spectrometers to gain information on the molecular alignment, but the results reported so far have been integrated over the emission direction of the secondary electron. 21,22 On the theoretical side, FDCSs for electron impact ionization of H 2 into the ground state of H 2 + have been investigated recently, 23-25 finding a distinct dependence of the electron scattering dynamics on the alignment. We have overcome this problem using a reaction microscope, which allows to measure many different kinematic settings at the same time.…”

Electron emission from fragmentation of CO2by fast proton impact

“…After our previous work on ionization of H 2 by fast protons [16,21], we now extend our study to the case of a polyatomic molecule, namely carbon dioxide. Besides its central role for a variety of chemical reactions in living organisms, CO 2 is a prototype of a linear triatomic molecule and is particularly important for atmospheric modelling since it is a constituent of planetary atmospheres.…”