Optical absorption spectra of palladium doped gold cluster cations

Abstract

Photoabsorption spectra of gas phase Aun+ and Aun-1Pd+ (13 ≤ n ≤ 20) clusters were measured using mass spectrometric recording of wavelength dependent Xe messenger atom photodetachment in the 1.9-3.4 eV photon energy range. Pure cationic gold clusters consisting of 15, 17, and 20 atoms have a higher integrated optical absorption cross section than the neighboring sizes. It is shown that the total optical absorption cross section increases with size and that palladium doping strongly reduces this cross section for all investigated sizes and in particular for n = 14-17 and 20. The largest reduction of optical absorption upon Pd doping is observed for n = 15.