Argon Solvent Effects on Optical Properties of Silver Metal Clusters

Abstract

Argon gas at a high pressure (∼80 bar) has been expanded using a miniaturized pulsed valve at room temperature, producing a supersonic beam of cold, large argon droplets. Atoms of silver are subsequently embedded into the droplet using the pick-up technique. The resulting Ag n Ardroplet distribution was analyzed using multiphoton laser ionization time-of-flight mass spectrometry. Besides bare metal clusters, snowballs of silver monomers and dimers encapsulated in up to 50 argon atoms have been observed. The influence of the solvent on the optical absorption of the solute was studied for embedded Ag8 using resonant two-photon ionization in the ultraviolet. A redshift and broadening of the Ag8Ardroplet optical spectrum compared to that measured in pure [Federmann et al., Eur. Phys. J. D 1999, 9, 11] and Ar-doped helium droplets [Diederich et al., J. Chem. Phys. 2002, 116, 3263] was observed, which is attributed to the interaction with the larger Ar matrix environment.

Solvation of Silver Ions in Noble Gases He, Ne, Ar, Kr, and Xe

“…The sequence 12, 32, and 44 has been observed in later work involving ions solvated in either helium or H 2 , and it is observed in the present work for H 2 O + solvated in helium. The sequence has been attributed to three concentric solvation shells of icosahedral symmetry containing 12, 20, and 12 ligands, respectively. − The interpretation is consistent with theoretical work. − Ar n Ag + and Ar n Ag 2 + showed no clear abundance anomalies , while the distribution of Ar n Ag 2+ suggested enhanced stability for n = 4 and 6 …”

“…In later work the Rostock group reported optical spectra of silver clusters that were synthesized by passing a supersonic beam of argon clusters through a pickup cell filled with silver vapor . Fielicke et al have recorded vibrational spectra of Ag 3 and Ag 4 by subjecting silver clusters tagged with argon atoms to tunable infrared radiation; a resonant loss of argon atoms was then detected by softly ionizing Ar n Ag m with a UV laser near the ionization threshold .…”

Effects of Rare-Gas Matrices on the Optical Response of Silver Nanoclusters

“…Optical absorption spectra for silver clusters embedded in helium nanodroplets [23][24][25] and argon nanodroplets 26 have been reported too. Particularly, the optical spectra of rare gas-doped silver clusters in a helium droplet, Ag8RGN@Hedroplet, have showed that the doping with RG=Ar, Kr, Xe leads to a shift of the mean resonance position which depends on the nature and the number N of attached atoms 24 .…”

Production of cluster complexes by cluster–cluster collisions—incorporation of a size-selected cobalt dimer ion into a neutral argon cluster

“…This method should be compared with the production of a metal cluster in (or on) a rare-gas cluster by using a pick-up cell. [13][14][15][16][17]22 For example, a silver cluster has been produced in an argon cluster by the pick-up of silver atoms, and optical properties have been measured at a low temperature. 22 In contrast, without preparing rare-gas clusters in advance, a cryogenic dri tube or ion trap is also utilized to attach helium atoms onto an ionic RSC Advances PAPER species.…”

“…[13][14][15][16][17]22 For example, a silver cluster has been produced in an argon cluster by the pick-up of silver atoms, and optical properties have been measured at a low temperature. 22 In contrast, without preparing rare-gas clusters in advance, a cryogenic dri tube or ion trap is also utilized to attach helium atoms onto an ionic RSC Advances PAPER species. [23][24][25] More generally, argon-attached metal clusters have been produced in argon-mixed carrier gas, 26,27 and their optical absorption spectra have been measured.…”