title: Photoinduced surface dynamics of CO adsorbed on a platinum electrode.
abstract: The surface dynamics of adsorbed CO molecules formed by dissociative adsorption of HCHO at a polycrystalline Pt electrode/electrolyte solution interface was studied by picosecond time-resolved sum-frequency generation (TR-SFG) spectroscopy. A SFG peak at 2050-2060 cm(-1) was observed at the Pt electrode in HClO(4) solution containing HCHO at 0-300 mV (vs Ag/AgCl), indicating the formation of adsorbed CO at an atop site of the Pt surface as a result of dissociative adsorption of HCHO. The peak position varied with potential by approximately 33 cm(-1)/V, as previously found in an infrared reflection absorption spectroscopy (IRAS) study. Irradiation of an intense picosecond visible pulse (25 ps, 532 nm) caused an instant intensity decrease and broadening of the CO peak accompanied by the emergence of a new broad peak at approximately 1980 cm(-1) within the time resolution of the system. These results suggest a decrease and increase in the populations of CO adsorbed on atop and bridge sites, respectively, upon visible pump pulse irradiation.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Noguchi
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Okada
authors.forename: Kohei
authors.initials: K
authors.lastname: Uosaki
mesh_terms: D000327:Adsorption; D002248:Carbon Monoxide / Q000737:chemistry* / Q000528:radiation effects*; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry; D005557:Formaldehyde / Q000737:chemistry / Q000528:radiation effects; D008027:Light; D010984:Platinum / Q000737:chemistry* / Q000528:radiation effects*; D012680:Sensitivity and Specificity; D012996:Solutions / Q000737:chemistry; D013057:Spectrum Analysis / Q000379:methods; D013499:Surface Properties / Q000528:radiation effects; D013997:Time Factors
chemical_list: D004573:Electrolytes; D012996:Solutions; D005557:Formaldehyde; D010984:Platinum; D002248:Carbon Monoxide