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

Abstract

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)

Thermal radiation of gold clusters on microsecond time scales

“…1(b) at t = 0 and for λ = 355 and 532 nm. The monomer (squares)-dimer (circles) evaporation branching ratios observed here are similar to those reported in [12]. Triangles show the sum of the monomer and dimer branches.…”

Formation of neutral clusters during sputtering of gold

“…The increase to a relatively constant cross-section for clusters of more than n atoms agrees with previous results for Ag [7]. However we observe an odd-even variation in cross-section which is much greater than observed for Ag [7] or In [28], but which is similar to that seen for Au clusters ionised with 355 or 266 nm light [1].…”

“…Such clusters are interesting because they will often have properties different to those of bulk materials. Typically the stability and structure of clusters have been studied using clusters prepared in the ground state by laser desorption of clusters into a cooling gas [1], complementing theoretical studies [2] of cluster energetics and structure. Clusters may also be generated using sputtering [3] and are commonly studied in the charged state using secondary ion mass spectrometry [4].…”

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.…”