Adsorption of CO and NO on surface studied by infrared-visible sum frequency generation spectroscopy

Interaction of Nitrogen Oxide and Carbon Molecules Adsorbed on Ni Clusters Formed on the MgO(111) Thin Film Surface

“…According to the results of experimental investigation [9,10] and theoretical calculations [11,12], the charge of the valence electron shell of these atoms is significantly polarized in the direction of the oxide, which in some cases causes adatom ionization. Analogous situation is observed in this case as well, since the wave number of line A is close to 2154 cm -1 characteristic for the CO molecules adsorbed on the NiO surface [13]. This correspondence additionally confirms the assumption that the displacement of the portion of CO molecules from the Ni metal cluster surface to the metal-oxide boundary is induced by the adsorption of the NO molecules.…”

“…This was manifested primarily in the decreased intensity of high-temperature peak B at 480 K and in the occurrence of new desorption line A at a temperature of 380 K. A comparison of the thermal desorption and IR spectra suggests that the same particles are responsible for the occurrence of both vibrational and desorption special features designated by symbol A. The comparable intensities of the 13 СО desorption lines before and after adsorption of the NO molecules pointed out to the fact that the observed cardinal reduction of the IR CO absorption line intensity at adsorption of the NO molecules was caused by the transformation of the properties of molecules on the surface rather than by the decrease in the surface CO concentration (for example, due to desorption). At least two reasons can be responsible for the observed decrease in the IR CO absorption line intensity at adsorption of the NO molecules: 1) a decrease in the dynamic dipole moments of molecules having components perpendicular to the surface (the method of IR spectroscopy in this configuration is sensitive only to these components) and 2) changes in the center and/or geometry of adsorption of the CO molecules.…”

Sum Frequency Generation Study of CO Adsorption on Palladium Model Catalysts

“…The weak SFG signals of hollow and bridged CO as compared with IRAS findings are probably related to the low Raman polarizability specific of multiple-coordinated CO [32][33][34] or may originate from an interference effect between different SFG susceptibility tensor elements as shown by Baldelli et al [35].…”

Molecules at Surfaces and Interfaces Studied Using Vibrational Spectroscopies and Related Techniques

“…Studies of this kind can be extended to higher temperature investigation, to follow reaction intermediates in heterogeneous processes. 67 We note, in passing, that interesting vibrational studies of adsorption on a well-defined oxide surface [MgO(100) 68 and NiO (111) 69 ] have also been reported, underscoring the usefulness of the IR-visible SFG technique for a wide variety of surfaces.…”