Tricapped tetrahedral Ag-7: A structural determination by resonance Raman spectroscopy and density functional theory

The resonance Raman spectrum of Ag-7, mass selected out of a cation beam of sputtered silver, neutralized, and codeposited with solid Ar, is presented . By comparing the observed spectrum with one calculated using density func tional theory one concludes the structure of the silver septamer to be a tr icapped tetrahedron. A partial resonance Raman spectrum of Ag-9 is also inc luded. Both spectra are dominated by totally symmetric "breathing" modes at similar to 165 cm(-1) (as is also true for Ag-5 [T. L. Haslett , J. Chem. Phys. 108, 3453 (1998)]). This frequency is close to the Debye frequency (1 56 cm(-1)) of solid silver, implying that the nature of the chemical bond i n these silver clusters already approximates closely that which exists in b ulk silver. (C) 1999 American Institute of Physics. [S0021-9606(99)00243-3] .