The dissociation channels of silver clusters Agn+, 3 ≤ n ≤ 20

Krückeberg, S.; Dietrich, G.; Lützenkirchen, K.; Schweikhard, L.; Walther, Clemens; Ziegler, J.

doi:10.1016/s0168-1176(96)04412-6

Cited by 63 publications

(35 citation statements)

References 44 publications

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“…In addition, odd-number silver cluster ions tended to lose two silver atoms in their dissociation while even-number clusters lose a single atom. 14 The magic numbers are in good agreement with the jellium model theory. 13,15 In the jellium model 15,16 one assumes that the positive ions of the cluster are smeared into a uniform background of spherical shape with density equal to that in the bulk.…”

supporting

confidence: 68%

Direct Formation of Silver Cluster Ions from Silver Salts by Laser Desorption/Ionization

Choi

Ha²,

Lee³

et al. 2007

Bulletin of the Korean Chemical Society

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Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) has been used to characterize a wide range of polymers. [1][2][3][4][5] In a MALDI mass spectrum, the protonated molecule and cation adduct of an analyte give an important information about the molecular ion mass. Some researchers reported that sliver clusters can be effectively produced under MALDI conditions from various silver salts in the presence of various matrices. [6][7][8][9] During the analysis of organic molecules when Ag + is used as the cationization agent, it can be recognized that besides the desired adduct ions, [M + Ag] + , an additional silver cluster ions, Ag n + is formed. Kéki and coworkers 7 studied the matrix effect on the formation of the silver cluster ions under MALDI conditions using reductive polar organic matrices and silver trifluoroacetate (AgTFA) and reported that the matrix greatly influenced the resulting cluster ion abundances.Metal clusters are very important in both theoretical and practical points of view. Investigation of cluster formation in mass spectrometry provides valuable information on the stability and electronic properties of clusters of different size. Studies on the formation of silver cluster ions under MALDI conditions have been performed in the presence of matrices such as 2,5-dihydroxybenzoic acid (DHB), 3,5-dimethoxy-4-hydroxycinnamic acid (sinapinic acid, SA), trans-3-indoleacrylic acid (IAA), 2-(4-hydroxyphenylazo)-benzoic acid (HABA), all-trans-retinoic acid (RTA), and 1,8,9-trihydroxyanthracene (dithranol, DIT).7-10 Formation of silver cluster ions directly from silver salts in the absence of matrix was not studied. In the present work, we investigated the silver cluster ions formed directly from silver salts of silver benzoate (AgBz), AgTFA, silver nitrate (AgNO 3 ), and silver p-toluenesulfonate (AgTS) in the absence of any matrices. Scheme 1 shows their chemical structures.Figures 1, 2, 3, and 4 are the laser desorption/ionization (LDI) mass spectra of AgBz, AgTFA, AgNO 3 , and AgTS, respectively. Only the mass spectrum of AgBz shows a clear distribution of the silver cluster ions. It is a surprising result that the silver cluster ions are directly formed from AgBz in the absence of any matrix. Macha and coworkers 9 investigated the formation of silver clusters from silver salts such as AgTFA, AgNO 3 , and silver acetylacetonate [Ag(acac)], but silver clusters were not detected. The cluster ion intensity distribution of AgBz shows an odd-even alternation pattern as shown in Figure 1. In other words, the intensity of the odd-number cluster ions tends to be stronger than that of the neighboring even-number cluster ions, especially in the low-mass range. The mass spectrum also shows a steep decrease of the ion intensities after some cluster ions called magic numbers. Figure 1 shows clear magic numbers of n = 9 and 21 of Ag n + . The specific ion intensity distribution of the silver cluster ions can be explained with the theoretical models.10-13 Since odd-number sil...

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supporting

confidence: 68%

Direct Formation of Silver Cluster Ions from Silver Salts by Laser Desorption/Ionization

Choi

Ha²,

Lee³

et al. 2007

Bulletin of the Korean Chemical Society

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“…The fragmentation pathways of singly charged metal clusters have been studied for several monovalent elements [1][2][3][4][5][6][7][8][9][10][11][12] and are an important tool in understanding cluster energetics and dynamics. After moderate excitation above their dissociation threshold singly charged metal cluster ions show a competition between the evaporation of a single neutral atom and a neutral dimer…”

Section: Introductionmentioning

confidence: 99%

“…Studies of the alkali-metal clusters Li + n (n = 4-42) [1], Na + n (n = 5-40) [2] and K + n (n = 5-200) [3], and of the monovalent noble metal clusters Cu + n (n = 2-17) [5,12], Ag + n (n = 3-21) [4,6] and Au + n (n = 3-23) [7] show that small odd-numbered clusters of these elements evaporate a neutral dimer while the other cluster sizes evaporate neutral monomers. A similar behavior has also been found for anionic clusters, Cu − n (n = 2-8) [10], Ag − n (n = 2-11) [9] and Au − n (n = 2-15) [8,11].…”

Section: Introductionmentioning

confidence: 99%

Decay pathways of small gold clusters

Vogel

Hansen

Herlert

et al. 2001

The European Physical Journal D

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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

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“…For most clusters of group-11 metals (copper, silver and gold), neutral monomer evaporation is the only relevant decay pathway. For some cluster sizes, however, neutral dimer evaporation is known to be a strong competitor [1][2][3][4][5][6][7][8][9][10][11][12][13]. This competition can be described in terms of the statistical nature of the unimolecular dissociation process.…”

mentioning

confidence: 99%

Photodissociation of small group-11 metal cluster ions: Fragmentation pathways and photoabsorption cross sections

Vogel

Herlert

Schweikhard

2003

J. Am. Soc. Mass Spectrom.

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Noble metal cluster ions Cu n ϩ , Ag n ϩ and Au n ϩ (n ϭ 3-21) have been stored in a Penning trap and photodissociated by low intensity laser pulses of 10 ns at photon energies of 3.49 eV and 4.66 eV. The fragmentation pathways, neutral monomer and dimer evaporation, have been monitored as a function of cluster size, excitation energy and element. It is found that the behavior of the branching ratio between monomer and dimer evaporation as a function of excitation energy depends on the metal under investigation. In particular, the slope of the energy dependence is positive for silver but negative for gold and copper cluster ions. Furthermore, photoabsorption cross sections are determined from observed total fragment yields in single-photon dissociation. (J Am Soc Mass Spectrom 2003, 14, 614 -621)

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The dissociation channels of silver clusters Agn+, 3 ≤ n ≤ 20

Cited by 63 publications

References 44 publications

Direct Formation of Silver Cluster Ions from Silver Salts by Laser Desorption/Ionization

Direct Formation of Silver Cluster Ions from Silver Salts by Laser Desorption/Ionization

Decay pathways of small gold clusters

Photodissociation of small group-11 metal cluster ions: Fragmentation pathways and photoabsorption cross sections

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