ELECTRIC-FIELD-INDUCED SHIFTS OF VIBRATIONAL FREQUENCIES OF CO ADSORBED ON NI, PD, PT, CU, AG AND AU METAL (100) SURFACES - A THEORETICAL COMPARATIVE-STUDY

A theoretical comparative study of electric field(F)-induced vibration al frequency shifts of CO adsorbed on Ni, Pd, Pt, Cu, Ag and Au metal (100) surfaces is presented. The calculated vibrational tuning rates d omega(C-O)/dF for the various metals are similar, thereby corroborati ng the experimental results of Ikezawa et al. The calculated absolute values are close to Lambert's observed values for CO on Ni in ultrahig h vacuum (UHV). The resulting estimates of the vibrational tuning rate with potential V are in qualitative agreement with experimental data in aqueous electrolytes. The small experimental value of tuning rate f or CO on Pt in UHV is not supported by the calculation. The M-CO bondi ng properties and their trends among the metals are also investigated.