The Mainz Cluster Trap

Schweikhard

2011

Appl. Phys. B

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Gold-cluster dianions Au 2− n , n = 21-31, have been investigated by use of multi-collisional excitation in a Penning trap. At low excitation energies the corresponding singly charged cluster anions have been observed, but no fragments, which indicates the emission of one electron. The binding energy of the surplus electron is deduced from the dianion yield observed as a function of the collision energy by use of a statistical model based on detailed balance. The resulting binding energies of the second electrons are in good agreement with a simple liquid-drop model with empirical corrections including the Coulomb barrier. The double difference of these energies shows a strong odd-even staggering which is compared to the behavior of the electron affinity of neutral gold clusters.

Section: Methodsmentioning

confidence: 99%

Electron binding energies from collisional activation of metal-cluster dianions

Schweikhard

2011

Appl. Phys. B

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“…A detailed description of the experimental setup and various aspects of the use of Penning traps has already been given elsewhere [13][14][15]. In general, the experimental procedure consists of the following steps: -The cluster ions are produced in a Smalley-type laser vaporization source [16,17].…”

Section: Experimental Methodsmentioning

confidence: 99%

Decay pathways of small gold clusters

Vogel

Hansen

The European Physical Journal D

et al. 2001

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Abstract. The decay pathway competition between monomer and dimer evaporation of photoexcited cluster ions Au + n , n = 2-27, has been investigated by photodissociation of size-selected gold clusters stored in a Penning trap. For n > 6 the two decay pathways are distinguished by their experimental signature in time-resolved measurements of the dissociation. For the smaller clusters, simple fragment spectra were used. As in the case of the other copper-group elements, even-numbered gold cluster ions decay exclusively by monomer evaporation, irrespective of their size. For small odd-size gold clusters, dimer evaporation is a competitive alternative, and the smaller the odd-sized clusters, the more likely they decay by dimer evaporation. In this respect, Au + 9 shows an anomalous behavior, as it is less likely to evaporate dimers than its two odd-numbered neighbors, Au

“…The experimental setup has been been reviewed recently [15,16]. The clusters are produced by laser vaporization of a metal wire in the presence of a helium gas pulse [17].…”

Section: Methodsmentioning

confidence: 99%

Observation of multiply charged silver-cluster anions

The European Physical Journal D

Schweikhard

Vogel

2001

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Singly charged silver-cluster anions are produced in a laser vaporization source and transferred into a Penning trap. After size selection the clusters are subjected to an electron bath in the trap, which results in the attachment of further electrons. The relative abundance of dianions or trianions as a function of the clusters' size is analyzed by time-of-flight mass spectrometry. Silver-cluster dianions are observed for sizes n ≥ 24 and trianions for n > 100. In addition, a detailed study of the cluster sizes 24 ≤ n ≤ 60 shows a pronounced resistance to electron attachment for singly charged anions Ag − n with a closed electronic shell, in particular Ag − 29 , Ag − 33 , and Ag − 39 . Both the threshold size for the observation of dianionic silver clusters and the shell effects in the production yield correlate favorably with previous theoretical investigations of the respective electron affinities. PACS. 36.40.Wa Charged clusters -36.40.Qv Stability and fragmentation of clusters -36.40.Cg Electronic and magnetic properties of clusters