Ionization and excitation of hydrogen molecules by fast proton impact

Abstract

The ratio of ionization - excitation to single ionization of hydrogen molecules caused by fast proton impact was measured over a wide velocity range (v = 6 - 24 au) using the coincidence time-of-flight technique. This ratio, %, is independent of the collision velocity at high velocities. It differs from the ratio of total to production mostly due to a large contribution from the dissociation of the electronic ground state of the molecular ion. The dissociation fraction of was measured and compares well with our calculations using the Franck - Condon approximation.

Kinematically Complete Study of Dissociative Ionization ofD2by Ion Impact

“…Relative contributions to dissociative ionization from the different processes are as follows: DSI, 7:3 1:8%; AI, 13:0 2:7%; IE, 64:6 7:5%; DI, 15:1 4:4%. The contribution of DSI to the total nondissociative single ionization is 0.48%, close to the value 0.485% determined by Ben-Itzhak et al [27].…”

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

“…1). Second, with a small probability of a few percent of all ionization events [22,26] (2) in Fig. 1).…”

“…[16][17][18][19][20][21]). During the previous decades, dissociative ionization of H 2 has been extensively studied by measuring the energy distributions of the emitted H + and/or the cross sections of the different channels [22][23][24].…”

“…Ionization plus excitation can be separated from ground state dissociation using the fact that the kinetic energy of the H + from the former is typically of the order of a few eV, whereas from the latter it is in the sub-eV range [23,27]. As an additional channel, double excitation of H 2 into autoionizing states is known to contribute within a few percent to the dissociative ionization [22,24]. Here, we are concerned with ground state dissociation (channel (2) in Fig.…”

Classical and semiclassical calculations of electron transfer cross sections inkeV-energy ion-molecule collisions

“…That is true over the entire range of impact energies, from slow ͑eV͒ to very fast ͑MeV͒ collision regimes. Restricting the discussion to nonreactive scattering, experimental studies of dissociative electron transfer, vibronic excitation, correlation, isomer effects, and post-collisional interaction effects are some of the most representative examples; see, e.g., [1][2][3][4][5][6][7][8][9][10][11][12] and references therein. For diatomic molecules electronic emission spectra have recently shown interference phenomena resulting in oscillatory relative double-differential cross sections [13][14][15].…”