The 488 nm negative ion photoelectron spectrum of Nb8, obtained at an instrumental resolution of ~5 meV, displays a clear vibrational progression in a mode with a frequency of 180 ± 15 cm-1 in neutral Nb8 and 165 ± 20 cm-1 in Nb8/-. The normal mode displacement of 0.4 ± 0.1 u( 1/2 ) Å indicates a very small geometry change upon electron detachment. The electron affinity of Nb8 is 1.513 ± 0.008 eV. These results are discussed in light of previous negative ion photoelectron spectroscopic and density functional studies of Nb8 and Nb8/-. (C) 2000 Elsevier Science B.V.
Bibliographical noteFunding Information:
We thank Dr. H. Grönbeck, Dr. W. Andreoni, and Dr. A. Rosén for sending us their ground state structures, and Dr. Evan Millam and Ms. Nancy Fleischer for their assistance with these experiments. We are grateful for Prof. Bob Squires’ insights on niobium cluster ion-molecule chemistry during his visit to our Department last May. Acknowledgement is made to the Donors of The Petroleum Research Fund, administered by the American Chemical Society, for support of this research.
- Metal clusters
- Metal ions
- Niobium clusters
- Photoelectron spectroscopy