A recent paper in this journal reported the synthesis and characterization via electrospray ionization mass
spectroscopy and UV-vis spectroscopy of (Au–Ag)144(SR)60 alloy nanomolecules with different compositions,
ranging from 1 : 0 to 1 : 0.75 Au : Ag ratios. The UV-vis spectra of such systems were found to
exhibit absorption peaks at 310 nm, 425 nm and 560 nm, interpreted as reminiscent of the silver surface
plasmon resonance band due to simple atomic replacement of Au by Ag atoms in a fixed structural
framework. On the basis of a comparison of experimentally observed and theoretically simulated optical
absorption spectra, we conclude that the experimental situation must be more complicated, and that
further work is needed to achieve atomistic insight into these fascinating systems.
