Fourier Transform IR Reflection Absorption Research Articles

In situ IR spectroscopic study of water at a polycrystalline gold electrode surface

The effect of the electrolyte anions on the water structure at the interface between a polycrystalline gold electrode and aqueous electrolyte solutions was studied using in situ Fourier transform IR reflection absorption spectroscopy (FT-IRAS). Considerably sharp absorption bands due to OH stretching modes of water were observed in the 3600–3500 cm−1 range in solutions containing F−, Cl−, Br−, I−, BF−4, ClO−4 or PF−6. The band intensity was found to be strongly dependent upon the electrode potential, while the band positions exhibited almost no potential dependence. The bands, however, appeared at different frequencies depending upon the electrolyte anions used, which strongly suggests that these water molecules should be in the hydration spheres of the anions. We also found that the potential dependent adsorption/desorption process of halide ions dominated the spectral feature of interfacial water, which was also supported by the double-layer capacitance measurements.

Surface reaction of organic materials by laser ablation of matrix-isolated photoreactive aromatic azido compound

The ablation of pentafluorophenylazide (FPA), which was isolated in a chemically inert C 6F 14 solid matrix at 85 K, was carried out by irradiation with a KrF excimer laser in vacuum. A large amount of pentafluorophenylnitrene (FPN) was ejected explosively as fragments from the matrix during irradiation. The photolysis of FPA was followed by mass spectrometry, UV–visible absorption spectroscopy and optical emission spectroscopy. It was found that the fragment beam of photolysed FPA was useful for the surface chemical modification of organic materials, such as a poly(ethylene terephthalate) film and alkylthiol monolayer. Surface analyses of these materials by X-ray photoelectron spectroscopy and Fourier transform IR reflection absorption spectroscopy indicated that FPN was immobilized on the surface through chemical bonding. The modified surface showed hydrophobic properties due to a decrease in surface polarity by the deposition of the fluorinated group of FPN. © 1997 Elsevier Science S.A.

Real-time in situ observation of photo-induced vapordeposition polymerization of N-vinylcarbazole with Fourier transform IR reflection absorption spectroscopy

By using a low pressure mercury lamp as an excitation source, vapor deposition polymerization (VDP)of N-vinylcarbazole was carried out. Deposition and annealing processes were observed with real-time in situ Fourier transform IR reflection absorption spectroscopy. On average, the film deposited at the substrate temperature of 255–275 Kconsisted of 65% of an isotropic component and 35% of an oriented component. A polymer yield of 95% film was obtained at a substrate temperature of 275 K. The same yield was achieved at an annealing temperature of around 350 K when the VDP film deposited at 255 K was annealed in vacuum.

Reduced CO 2 on polycrystalline Pd and Pt electrodes in neutral solution: electrochemical and in situ Fourier transform IR studies

Reduced CO 2 was found to be formed from CO 2 on Pd, and the characteristics of this reaction were studied in comparison with 0the reaction on Pt in phosphate buffer solution (pH 6.4) at room temperature by anodic stripping voltammetry (ASV), in situ Fourier transform IR reflection absorption spectroscopy (in situ FTIRAS), and Tafel plots. The most positive potentials for the formation of reduced CO 2 on Pd and Pt were found to be 0.05 V and 0.3 V (vs. RHE), respectively. Reduced CO 2 was assigned as adsorbed CO on both electrodes by in situ FTIRAS. The adsorption modes were bridged and three-fold CO on Pd, whereas linear CO was found on Pt. The adsorption affinity of reduced CO 2 at negative potentials on Pt was higher than that on Pd. This suggests that reduced CO 2 behaves as a catalytic self-poison for the electrochemical reduction of CO 2 on Pt, but it partly becomes an intermediate in the reduction of CO 2 on Pd.

Mechanism of X-ray-induced degradation of pyromellitic dianhydride

The degradation of pyromellitic dianhydride (PMDA) under X-ray exposure has been studied by a combination of X-ray photoelectron spectroscopy and Fourier transform IR reflection absorption spectroscopy. Vapor deposited PMDA films show significant degradation under prolonged X-ray exposure. The data indicate that the initial degradation reaction follows a unimolecular mechanism and includes cleavage of the anhydride rings with the release of CO 2 molecules, which are either trapped in the film or released into the vacuum.

ChemInform Abstract: In situ FT‐IR Spectroscopic Study of Bisulfate and Sulfate Adsorption on a Platinum Electrode. Part 2. Mildly Acid and Alkaline Sodium Sulfate Solutions.

AbstractThe adsorption behavior of sulfate and bisulfate ions on a Pt electrode in 0.5 M Na2SO4 solutions containing a small amount of H2SO4 (pH 3.4) or NaOH (pH 11.5) is studied in situ by potential difference FT‐IRRAS (Fourier transform IR reflection absorption spectroscopy).

Comparison of thermal stability of Langmuir-Blodgett films of icosanoic acid and cadmium icosanoate

The thermal stability of the Langmuir-Blodgett (LB) films of icosanoic acid and cadmium icosanoate was studied using Fourier transform IR reflection absorption spectroscopy and scanning electron microscopy. It was found that the thermal behaviour of icosanoic acid in LB films is quite different from that of cadmium icosanoate. For the icosanoic acid LB film, the fast progressive disordering with the desorption and migration of the acid molecules occurs with increasing temperature even below the bulk melting point, while for the cadmium icosanoate LB film the desorption and migration were hardly observed at temperatures below and around the bulk melting point. From the thermal cyclic experiments, it was found that the structural change of the LB film on heating was irreversible for icosanoic acid and was reversible for cadmium icosanoate in the temperature range below the bulk melting point.

Application of X-ray photoelectron spectroscopy and fourier transform IR-reflection absorption spectroscopy to studies of the composition of Langmuir-Blodgett films

The composition of icosanoic acid films deposited on substrates from an aqueous subphase containing metal such ions as cadmium, calcium, barium and lead at various pH values was investigated by X-ray photoelectron spectrocopy and Fourier transform IR-reflection absorption spectroscopy. It was found that the composition of the Langmuir-Blodgett films is changed by the pH of the subphase and that the pH range of formation of acid, salt and mixed films is characteristic for each metal ion. Also, the results obtained are in good agreement with the data of different methods of analysis.