Temporal Raman polarizabilities of piperidine in liquid and on the Ag surface with electromagnetic enhancement

The temporal bond polarizabilities from the Raman intensities for liquid piperidine and its adsorption on the Ag electrode were obtained. The bond polarizabilities are important molecular parameters which show the bond electronic behavior during the Raman process. For the liquid piperidine, it is noted that the bond polarizability at the final stage of relaxation of the Raman virtual state is parallel to the quantum chemically calculated bond electronic density of the ground state. This opens a new way to observe the bond electronic density simply from the experimental Raman spectrum. For the piperidine adsorbed on the Ag electrode, it is inferred from the elucidated bond polarizabilities that the electromagnetic mechanism dominates the surface enhanced Raman effect, showing that the equatorial C-H bond is enhanced more than its axial companion.