Detection using transient reflecting grating spectroscopy for the ultrafast interaction between photoexcited electrons and adsorbed molecules at a gold surface

We investigated photoexcited electron dynamics, which is considered to be r elated to the surface enhanced Raman scattering (SERS) effect, using the tr ansient reflecting grating spectroscopic method. Two kinds of vapor-deposit ed gold films were prepared as SERS substrates. One of them induced the SER S effect (SERS active substrate), while the other did not (SERS inactive su bstrate). For the SERS active substrate, only the electrons excited at L in the gold band structure decreased faster when crystal violet (CV) molecule s were adsorbed on the substrate, while no differences were observed betwee n CV adsorbed and CV non-adsorbed substrates for the SERS inactive substrat es. From these results, we concluded that excited electrons only around L i n the band structure of gold have some relation to the SERS effect.