Two-electron emission after photoexcitation of metal-cluster dianions

Abstract

Size-selected metal-cluster dianions of the elements gold, silver and copper have been photoexcited by nanosecond-pulse and continuous laser irradiation, which leads to electron emission and monomer evaporation. In addition to the observation of these competing decay pathways, there is a reduction of the total cluster-ion intensity, which indicates the neutralization of dianions, i.e. the loss of both surplus electrons. In contrast, the activation of singly charged anionic clusters of the same type results primarily in dissociation by monomer evaporation and not by electron emission. These decay processes as observed for doubly and singly charged cluster anions suggest that the dianions emit two electrons simultaneously, i.e. in a correlated fashion. A classical conducting-sphere approximation confirms that the Coulomb barrier for symmetric two-electron emission is lower than the Coulomb barrier for the emission of a single electron.

Electron attachment to anionic clusters in ion traps

“…6a). Thus, production and subsequent laser excitation of polyanionic clusters [34,[37][38][39] can be combined in an experimental sequence, where the electron beam and the laser beam enter the trap from the (Fig. 1) [17].…”

“…6c). Note that, in general, there is a size-dependent decay-pathway competition of electron emission and neutral-atom evaporation for dianions as well as further (possibly multiple) decay of the monoanions [37,39]. In order to disentangle the details of the decay sequences, future experiments will include size and charge-state separation prior to the laser irradiation.…”

Gas Phase Formation, Structure and Reactivity of Gold Cluster Ions

“…Schweikhard's group has widely studied the fragmentation reactions of bare gold cluster anions and cations in a Penning ion trap using a range of activation techniques including CID [170][171][172][173][174][175][176][177][178], PD [176,[179][180][181][182][183][184][185][186][187][188][189][190][191][192][193][194][195] and electron-induced dissociation (EID) [196][197][198][199][200][201]. The latter studies are discussed in Sect.…”

Single-Photon, Double Photodetachment of Nickel Phthalocyanine Tetrasulfonic Acid 4- Anions

“…These observations pave the way toward new, exciting experiments for probing double photodetachment at relatively low energies, including correlation measurements on emitted photoelectrons. 4 The detachment of two electrons from a gas-phase species via the absorption of a single photon is a common process that is observed in systems as diverse as neutral or charged atoms, small molecules, molecular anions and multiply charged proteins (Table 1) [1][2][3][4][5][6][7][8][9][10][11][12][13] . A range of mechanisms for double electron detachment are available, including processes such Auger emission, shakeoff processes, knock-out and relaxation following double excitation.…”