New Method for the Study of Dissociation Dynamics of State-Selected Doubly Charged Ions: Application toCO2+

Abstract

A new technique is described which is capable of observing the stability of specific states of doubly charged molecular ions with vibrational level resolution. The method is based on the process of double photoionization using synchrotron radiation. Pairs of threshold electrons identify the initial state, and the resulting ions are characterized by their times of flight. Lifetimes have been measured for specific levels of CO 21 and confirm, except for the very lowest levels, the intrinsic instability of this species on the ms time scale. [S0031-9007(98)

Photo double ionization spectra of CO: comparison of theory with experiment

“…The vibrational levels were determined using pairs of threshold electrons, and the resulting ions characterized by their time of flight. In this manner lifetimes of several states of CO 2+ were measured and found to have magnitudes of the order of microseconds [15]. The second measurement of vibrational lifetimes used three-dimensional fragment imaging [16] and enabled the simultaneous measurement of kinetic energy release upon dissociation and the lifetime of a given state.…”

Multielectron spectroscopy: Auger decays of the argon 2p hole

“…Indeed detailed studies have appeared recently since the introduction of electron / electron coincidence techniques in the field 1 . A partial and non exhaustive list of recent electron / electron coincidence experiments includes valence double ionization of atoms 2 and especially of He 3,4 , of molecules 2,5,6 and especially of H 2 , 7,8 and coincidence studies of Auger 9,10,11,12,13,14,15 and double Auger decays 16,17 . However in most of these examples only a small part of all the processes releasing several electrons is explored as most of the studies have restricted their coincidence detection system or the event analysis to processes where exactly 2 electrons are emitted.…”

Bond-Forming Chemistry in the Gas-Phase Reactions of Atomic and Molecular Dications and Trications

“…Since these early experiments, coincidence experiments of everincreasing sophistication have been used to probe the formation and unimolecular dissociation of dications and (more recently) trications. [10][11][12][13][14][15][16][17]66 The correlations between the TOFs of the pairs of ions in the earlier experiments reveal subtle details of the dynamics of the unimolecular dissociation process and have proved particularly powerful at probing the mechanisms of 'threebody dissociation reactions,' where a neutral species accompanies the pair of fragment ions: 65,67,68…”

“…[10][11][12][13][14][15][16][17][18] As is discussed in more detail later, coincidence experiments involve the simultaneous detection of two or more species that are formed in a single 'reactive' event. Thus, coincidence experiments are ideally suited for studying the formation and reactions of dications, where two or more charged species are usually involved.…”