ChemInform Abstract: Charge Shift of Adsorbed Pyridazine Molecules to the Silver Electrode Surface at Various Applied Voltages as Interpreted from the Surface Enhanced Raman Intensities.

Abstract

Abstract An algorithm which enables one to calculate the bond polarizability derivatives from the surface enhanced Raman (SER) intensities has been employed to study the adsorption of pyridazine molecules on the silver electrode. It is inferred from the bond polarizability derivatives that as the applied voltage varies from −0.4 V to −0.6 V the electron charge in the bonding orbital n 1 + n 2 , formed from the lone pair orbitals n 1 and n 2 of the two adjacent nitrogen atoms, shifts towards the silver electrode surface, whereas from −0.6 V to −0.8 V it is the charge in the antibonding orbital n 1 − n 2 that shifts towards the electrode surface. The corresponding SER frequencies of those modes involving the stretch motion of the NN bond initially decrease and then increase. At the same time a charge shift occurs in the benzene-like ring which obeys the bond conjugate rule.