Photoelectron spectroscopy of mono-niobium carbide clusters NbCn−(n=2–7): Evidence for a cyclic to linear structural transition
We investigated a series of mono-niobium carbide clusters, NbCn− (n=2–7), using anion photoelectron spectroscopy. Vibrationally resolved photoelectron spectra were observed for NbC2− and NbC3−, which were both shown to have cyclic C2v structures. Two isomers were observed for NbC4− and NbC5−. The we...
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Veröffentlicht in: | The Journal of chemical physics 2001-09, Vol.115 (11), p.5170-5178 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | We investigated a series of mono-niobium carbide clusters, NbCn− (n=2–7), using anion photoelectron spectroscopy. Vibrationally resolved photoelectron spectra were observed for NbC2− and NbC3−, which were both shown to have cyclic C2v structures. Two isomers were observed for NbC4− and NbC5−. The weak and low electron binding energy isomers were shown to be cyclic structures forming a series with NbC2− and NbC3−, and all have similar and low electron binding energies. The main isomers of NbC4− and NbC5−, which possess much higher electron binding energies, were shown to be due to linear structures, which form a series with NbC6− and NbC7−. All the linear NbCn− clusters were observed to have high electron binding energies and exhibit an even–odd alternation, similar to that observed for pure linear carbon clusters in the same size range. A cyclic to linear structural transition was thus observed for the NbCn− clusters from NbC3− to NbC4−, with the cyclic structures favored for the smaller clusters and the linear isomers favored for the larger clusters. |
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ISSN: | 0021-9606 1089-7690 |
DOI: | 10.1063/1.1395556 |