부산대학교 도서관

The electronic and geometric properties of gas-phase exohedral C[sub 60]Na[sub N][sup -], C[sub 70]Na[sub N][sup -], and C[sub 60]Au[sub N][sup -] cluster anions are investigated. Time-of-flight mass spectrometry and photoelectron spectroscopy (PES) reveal complex-specific arrangements of the sodium and the gold atoms on the fullerene cage. The electron affinity of C[sub 60]Au[sub N] clearly shows even-odd alternation with the number of Au atoms, which suggests a "dry" structure where Au atoms aggregate as a cluster on the C[sub 60]. In contrast, C[sub 60]Na[sub N] and C[sub 70]Na[sub N] show a "wet" structure having the Na atoms packed into stable trimers on the surface. For C[sub 60]Na[sub N] (N=0 to 4), PES experiments at a high photodetachment energy (5.81 eV) allow us to deduce the net charge transferred from the sodium atoms to the lowest unoccupied molecular orbital of the fullerene. For larger C[sub 60]Na[sub N], moreover, a metallic transition is shown to occur at N∼13, and analysis of the adiabatic electron affinity variations allows the identification of the first magic sizes corresponding to electronic shell closure in the sodium layer. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]