Polarization modulated infrared reflection absorption spectroscopy

The three most commonly applied external reflectance techniques can be considered in terms of the means employed to overcome the sensitivity problem. Both electrically modulated infrared spectroscopy (EMIRS) and in situ FTIR use potential modulation while polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) takes advantage of the surface selection rule to enhance surface sensitivity. [Pg.103]

Sum Frequency Generation and Polarization-Modulation Infrared Reflection Absorption Spectroscopy of Functioning Model Catalysts from Ultrahigh Vacuum to Ambient Pressure... [Pg.133]

PMIRRAS polarization modulation infrared reflection-absorption spectroscopy... [Pg.126]

The technique using p-s modulation has received different names depending on the kind of IR instrument used. Thus for grating instruments it was called PMIRRAS (polarization modulation infrared reflection-absorption spectroscopy) [6]. For FT spectrometers the name FTIRRAS [8] was suggested. However this name was later used also in connection with Fourier transform spectra applying the potential difference approach. [Pg.137]

Rupprechter G (2007) Sum frequency generation and polarization-modulation infrared reflection absorption spectroscopy of functioning model catalysts from ultrahigh vacuum to ambient pressure. Adv Catal 51 133... [Pg.342]

Ozensoy E, Meier D, Goodman D (2002) Polarization modulation infrared reflection absorption spectroscopy at elevated pressures CO adsorption on Pd(lll) at atmospheric pressures. J Phys Chem B 106 9367... [Pg.344]

Kocharova N, Leiro J, Lukkari J et al (2008) Self-assembled carbon nanotubes on gold polarization-modulated infrared reflection-absorption spectroscopy, high-resolution X-ray photoemission spectroscopy, and near-edge X-ray absorption fine structure spectroscopy study. Langmuir 24 3235-3243... [Pg.432]

During this work, we analyzed the organization, the morphology, and the preferential adsorption of these copolymers and how these properties would be influenced by the interfacial interactions that could be established between the polymer and the chemical functionalities grafted onto the adsorption substrate. Our results were mainly based on two surface techniques polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS) and atomic force microscopy (AFM). [Pg.49]

Polarization-Modulation Infrared Reflection-Absorption Spectroscopy (PM-IRRAS)... [Pg.50]

Polarization-modulation infrared reflection-absorption spectroscopy (PM-IR-RAS) spectra were recorded with a Bruker ITS 66/S Fourier transform infrared spectrometer equipped with a PMA 37 polarization modulation module and a ititrogen-cooled MCT detector. The infrared beam was first p-polarized with a ZnSe wire grid polarizer (Specac) before passing through a photoelastic modulator (Hinds Instruments, PEM-90), which modulated at a frequency of 74 kHz. A lock-in ampHfier (Stanford model SR-830) was used to obtain the PM-IRRAS spectra. The half-wave retardation frequency was set at 4000 cm . The PM-IR-RAS spectra were recorded as S= R -Rs)/(R +Rg). A total of 250 scans at a resolution of 4 cm were collected for each measurement at an angle of incidence of 82.5° with respect to the normal to the sample surface. [Pg.291]

One of the most commonly applied IR techniques developed to overcome these problems is the external reflectance technique. In this method, the shong solvent absorption is minimized by simply pressing a reflective working electrode against the IR transparent window of the electrochemical cell. The sensitivity problem, that is, the enhancement of the signal/noise ratio in the case of external reflectance techniques is solved by various approaches. These are, for instance, electrochemically modulated infrared spectroscopy (EMIRS), in situ FTIR (which use potential modulation), and polarization modulation infrared reflection absorption spectroscopy (PM-IRAS, FTIR) [86,117-123]. [Pg.367]

Meier et al. [166] applied polarization-modulation infrared reflection absorption spectroscopy (PM-IRAS) to simultaneously monitor hquid phase and adsorbed species during benzyl alcohol selox over Pd(l 11). Anaerobic conditions favored CO surface accumulation via decarbonylation, while surface oxygen fadhtates CO oxidation, leaving no surface residues strongly adsorbed CO and oxygen poison the active surface sites. [Pg.30]

The second means of increasing the S/N ratio, which has also been employed with FTIR spectrometers, involves modulating the polarization state of the light, a technique termed polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). This technique relies on a subsidiary selection rule, valid... [Pg.140]

A second lock-in detection method that was employed is polarization modulation, which involves modulating the polarization state of the incident infrared beam, and is again an extension of an approach developed for the study of the gas-solid interface [80]. Polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS) relies upon the principles underlying the surface selection rule... [Pg.536]

The complexation of PABA with nucleotides was further studied using polarization modulated infrared reflection absorption spectroscopy (PM-IRRAS). PM-IRRAS spectra of PABA films exhibit all the characteristic vibrations of polyaniline and boronic acid (Figure 3.27) [93, 94]. After complexation with NAD+ (Figure 3.27, b) and NADH (Figure 3.27, c), the disappearance of the free B-OH group vibration at 986 cm and increase in the intensity of the asymmetric B-O bond vibration at 1330 cm indicate the formation of boronate ester. The new vibrations at 1080 and 1470 cm have been attributed to ribose and adenine moieties, respectively [153]. The vibrations at 1218 (NAD+), 1245... [Pg.192]

Brand, I., Nulhneier, M., KltiNer, T., Jogireddy, R., Christoffers, J., Wittstock, G., 2009. Stmctural analysis of HS(CD2)i2(0—CH2—CH2)60CH3 monolayers on gold hy means of polarization modulation infrared reflection absorption spectroscopy. Progress of the reaction with bromine. Langmuir 26, 362—370. [Pg.110]

Infrared Spectroscopy. Polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) data were collected using a Nicolet MAGNA-IR 860 Fourier transform spectrometer equipped with a liquid nitrogen-cooled mercury-cadmium-telluride (MCT) detector and a Hinds Instruments PEM-90 photoelastic modulator. The p-polarized light was incident at 80° from the surface normal. The spectra were collected for 1000 scans at a spectral resolution of 4 cm . ... [Pg.277]