Good vibrations: Metal–molecule–metal nanosystems are fabricated by the self‐assembly of gold and silver nanoparticles interconnected with 4‐aminothiophenol (PATP) molecules (see picture). The b2 vibrational modes of the PATP molecules are greatly enhanced by near‐infrared excitation, as a result of charge transfer between the metal nanoparticles coupled with the vibrations of the PATP molecules.

Excess infrared (IR) absorption spectroscopy, a new concept brought forward by applying the idea of excess thermodynamic functions to infrared spectroscopy, is shown to be a potential method to study hydrogen bonds. It can be applied to enhance spectral resolution of complexed IR bands, to evaluate nonideality of liquid mixtures, and to estimate selective molecular interactions. The sign of the excess infrared absorption coefficient is also of importance in providing information on molecular interactions. The results demonstrate that excess infrared absorption spectroscopy can unveil new information on hydrogen bonding in condensed phases.

No abstract

No abstract

Molecular junctions of metal/molecule/metal were fabricated with silver nanoparticles and functional molecules through layer-by-layer self-assembly techniques. The Raman scattering of the interconnecting molecules between the silver nanoparticles can be greatly enhanced. For the silver/4-aminothiophenol/silver (Ag/PATP/Ag) assembly, in particular, the larger enhancement of the b 2 modes, relative to that of the a 1 modes, is ascribed to the charge transfer between the silver nanoparticles tunneling through the interconnecting PATP molecules. The molecular dipolar momentum and surface property of the silver nanoparticles have large effects on the enhancement of the Raman scattering of the interconnecting molecules.