William P. McKenna

Applications of Fourier transform infrared photoacoustic spectroscopy (FT-IR / PAS) to surface and corrosion phenomena

The development of FT-IR / PAS as a surface analytical technique is described by analytical studies presented in this paper. Studies have focused on the use of FT-IR / PAS alone, both qualitatively and quantitatively, and in comparison with X-Ray Photoelectron Spectroscopy (XPS or ESCA) and have yielded a variety of information, especially in the realm of polymer, catalyst and corrosion applications. Spectral information from FT-IR / PAS includes an enhanced surface response and thermal properties convoluted with the normal infrared vibrational absorption function. Analysis of catalyst surfaces provides an example of the unique capabilities of FT-IR / PAS to provide qualitative and quantitative information about both gas phase and adsorbed species. Kinetics of reactions can be followed in real time. The utility of FT-IR / PAS in conjunction with ESCA is illustrated by the analysis of an Fe/NH3/HCN corrosion product, where unambigous assignment of the resulting compounds allowed explanation for the observed pitting corrosion.

Ftir photoacoustic investigation of the surface species resulting from the photochemical reaction of Re2(CO)10 with silica and alumina

Abstract The photolysis of Re 2 (CO) 10 in the presence of Cab-O-Sil silica and alumina has been investigated by FTIR/PAS methods. The formation of tricarbonyl species on the surface of both oxides has been observed. The formation of tetracarbonyl and pentacarbonyl surface species during photolysis in THF slurries has also been postulated. A comparison of the photolysis in benzene and THF has been undertaken, and benzene appears to promote tricarbonyl formation.

Infrared Photoacoustic Spectroscopy of Conducting Polymers III. Polyparaphenylene and its Derivatives

Fourier Transform Infrared Photoacoustic (FT-IR/PA) spectroscopy provides a means to obtain high quality spectra of polyparaphenylene (PPP), an organic semiconductor. Spectra of PPP prepared by two different methods, heavily n-doped PPP, and a new organometallic derivative, PPP(Mo(CO)3)0.25 are presented. Spectral acquisition times for these polymers can be as low as one minute.

An infrared study of thiocyanate at the mercury electrode interface

Abstract FTIR surface infrared spectroscopy of the mercury solution interface shows the adsorption of complex ions of mercury thiocyanate at potentials more positive than −200mV vs SCE, and indicates that thiocyanate ion is adsorbed by electrostatic physiadsorption at more negative potentials.

FT-IR/PAS investigation of chromocene supported on silica

Chromocene anchored on silica has been investigated by Fourier transform Infrared photoacoustic spectroscopy (FT-IR/PAS). The mid Infrared spectrum of this olefin polymerization catalyst has been obtained before and after treatment with ethylene. A model complex for a key intermediate in the olefin polymerization has been observed. The design of a vacuum jacketed PA cell for use in a vacuum bench FT-IR spectrometer is also presented.

FT-IR Photoacoustic Spectroscopy Investigation of Oxidized Wool

The Fourier transform infrared photoacoustic spectra (FT-IR/PAS) of wool, shrink-resist treated wool and corona discharge oxidized wool are reported. Products of the oxidation of wool by dichloroisocyanuric acid are discussed. The FT-IR/PAS results indicate the formation of a sulphinic acid residue during the wool treatment.

Far-IR studies of carbon acid complexes of 18-crown-6

Bands in the far-IR spectra of 18-crown-6 complexes of nitromethane, acetronitrile, and malonodinitrile are attributed to hydrogen bonding. The vσ vibrational mode is assigned for these neutral complexes. Solution studies of the complexes in CHCl3 show that a substantial amount of both the nitromethane complex and the malonodinitrile complex remains intact. The acetonitrile complex, however, appears to dissociate in CHCl3.

FT-IR/photoacoustic and 13C-CPMAS investigation of Mo2(C3H5)4 supported on silica and alumina

Abstract FT-IR/Photoacoustic spectra were obtained for Mo2(C3H5)4 supported on alumina and silica. It was found that the silica complex has both σ-allyl and π-allyl species present. In contrast, it was shown that the alumina complex is dominated by a π-allyl species. 13C-CPMAS NMR data were obtained for the alumina complex. It was found that the alumina complex undergoes fluxional behavior similar to that found for the Mo2(C3H5)4 species in solution. The results of these investigations suggest that the alumina complex possesses a metal-metal bond.

Far-IR spectroscopy of ammonium and oxonium complexes of 18-crown-6

The far-IR spectra for NH4+ and H3O+ complexes with 18-crown-6 have been obtained and the hydrogen-bond vibrational mode vσ has been assigned. These results illustrate the suitability of far-IR spectroscopy for exploring crown ether molecular ion interactions.