Asymmetries in the Electronic Properties of Spheroidal Metallic Nanoparticles, Revealed by Conduction Electron Spin Resonance and Surface Plasmon Resonance

Abstract

Using electron spin resonance spectroscopy, we demonstrate that the morphological asymmetries present in small spheroidal metallic nanoparticles give rise to asymmetries in the behavior of electrons held in states near the metal’s Fermi energy. We find that the effects of morphological asymmetries for these spheroidal systems are more important than the effects of size distributions when explaining the asymmetry in electronic behavior. This is found to be true for all the particles examined, which were made from Cu, Ag, Pd, Ir, Pt, and Au, bearing dodecanethiolate ligands. In the case of the Ag particles, we also demonstrate that the same model used to account for morphological effects in the electron spin resonance spectra can be used to account for small asymmetries present in the plasmon spectrum. This result demonstrates that the electronic properties of even small particles are tunable via morphological changes.

Magnetism of Atomically Precise Gold and Doped Nanoclusters: Delocalized Spin and Interparticle Coupling

“…In addition to the small-sized Au NCs discussed above, larger Au NCs with unpaired electron have also been reported and are even more intriguing as these NCs bridge up the small NCs possessing discrete energy levels with conventional plasmonic NPs possessing a quasi-continuous band. , The magnetism of atomically precise Au n (SR) m NCs can serve as an important indicator for the investigation on the transition from atomic magnetism (localized) to delocalized spin to band magnetism. Among the Au NCs of large sizes (>100 atoms of Au), the charge-neutral Au 133 (SR) 52 (81e) of 1.7 nm core diameter is a recent example, which illustrates a different EPR spectrum from that of Au 25 (SR) 18 (7e) .…”