ISSN:
1434-6079
Keywords:
36.40. +d
;
33.80.Rv
;
35.20.Vf
Source:
Springer Online Journal Archives 1860-2000
Topics:
Physics
Notes:
Abstract This article reviews the results of several recent experiments performed in our laboratory designed to elucidate the fundamental chemical and physical properties of clusters of both transition metals and other refractory elements containing from one to several hundred atoms. The gas-phase reactivity of clusters towards a variety of reagents is explored using a fast-flow reactor system. Strong cluster size-dependent variations in reactivity are observed, especially for the case of hydrogen chemisorption. Measurement of cluster photoionization thresholds (IPs) provides a sensitive probe of the evolution of cluster electronic structure as a function of the number of constituent atoms. Cluster ionization potentials are observed to exhibit fluctuations about the smooth global falloff predicted by the classical drop model, indicating the non-bulk-like behavior of small clusters. Measurement of shifts in IP induced by chemisorption of different reagents provides insight into the nature of adsorbate-cluster bonding. The formation and properties of bare and metal-doped carbon clusters are explored, with particular emphasis on elucidating the photophysics and photochemistry of the postulated ultrastable larger clusters. The results suggest that further work is required to prove soccer ball-like structures for C50, C60, etc. Finally, infrared multiple-photon dissociation (IR-MPD) is demonstrated to be a viable technique for obtaining infrared spectra of absorbate-cluster complexes. This technique is an important new tool for obtaining information about the molecularity of gas-phase reactions beyond that currently available from mass spectrometric analysis. As an illustration of the method, IR-MPD spectra of methanol chemisorbed on small iron clusters are obtained.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01384807
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