Polarizability and abnormal infrared spectra of molecules adsorbed on metal nanostructured surfaces

Based on the experimental results of abnormal infrared effects(AIREs) for molecules adsorbed on transition-metal nanostructured surfaces,the interactions and the polarizability of the adsorbed molecules are analyzed theoretically.By numerical simulations,the normal absorption spectrum,the Fano-like bipolar spectrum and the anti-absorption spectrum of the adsorbed CO molecules are obtained respectively.The results show that the adsorbed molecules on a metal nanostructured surface can accumulate together dues to the effect of local external electric field,which leads to a change in imaginary part of the molecular polarizability within a certain range of frequency,and even a negative value may appear.