Raman spectroscopy of adsorbed species on dry surfaces
Raman spectroscopy of adsorbed species on dry surfaces
Techniques have been developed that. greatly increase the sensitivity of laser Raman spectroscopy as a technique for, surface examination. A reliable method of sample preparation involving oxygen baking and a 'grease free' vacuum system has been developed to prevent sample fluorescence. This has led to the detection of Raman spectra at very low surface coverages. In addition a vacuurd cell in which the sample can be rotated has been constructed to prevent sample heating during laser irradiation.With the call and a Multiplex Raman Spectrometer, with which frequency shifts can be measured accurately, a series of coloured copper impregnated alumina catalysts were successfully studied. The behaviour of pyridine on both the coloured copper system and on the support alumina was investigated at very low coverages. This led to a detailed analysis. of the adsorption processes taking place and indicated that the copper ions were on the surface and accessible to pyridine. A similar study of benzene resulted in the detection of previously unseen frequency shifts for the ring breathing vibration. A non-specific monolayer adsorption was thought responsible for this shift which indicates an association of the benzene it orbitals with the surface.Using a conventional Raman spectrometer a series of adsorbates were investigated on a number of different surfaces. The adsorption of acetylene on 1-alumina led to the identification of polyacetylene and physisorbed acetylene on'-alumina and on a range of X-zeolites. Halogens were found to form a number of surface species on oxide surfaces. Bromine gives Bra and Br2OH as well as physisorbed gas. Chlorine undergoes a less specific interaction with the surface.
University of Southampton
1979
Heaviside, John
(1979)
Raman spectroscopy of adsorbed species on dry surfaces.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Techniques have been developed that. greatly increase the sensitivity of laser Raman spectroscopy as a technique for, surface examination. A reliable method of sample preparation involving oxygen baking and a 'grease free' vacuum system has been developed to prevent sample fluorescence. This has led to the detection of Raman spectra at very low surface coverages. In addition a vacuurd cell in which the sample can be rotated has been constructed to prevent sample heating during laser irradiation.With the call and a Multiplex Raman Spectrometer, with which frequency shifts can be measured accurately, a series of coloured copper impregnated alumina catalysts were successfully studied. The behaviour of pyridine on both the coloured copper system and on the support alumina was investigated at very low coverages. This led to a detailed analysis. of the adsorption processes taking place and indicated that the copper ions were on the surface and accessible to pyridine. A similar study of benzene resulted in the detection of previously unseen frequency shifts for the ring breathing vibration. A non-specific monolayer adsorption was thought responsible for this shift which indicates an association of the benzene it orbitals with the surface.Using a conventional Raman spectrometer a series of adsorbates were investigated on a number of different surfaces. The adsorption of acetylene on 1-alumina led to the identification of polyacetylene and physisorbed acetylene on'-alumina and on a range of X-zeolites. Halogens were found to form a number of surface species on oxide surfaces. Bromine gives Bra and Br2OH as well as physisorbed gas. Chlorine undergoes a less specific interaction with the surface.
This record has no associated files available for download.
More information
Published date: 1979
Identifiers
Local EPrints ID: 460238
URI: http://eprints.soton.ac.uk/id/eprint/460238
PURE UUID: b92283f0-560f-4a50-9202-d27745ee0826
Catalogue record
Date deposited: 04 Jul 2022 18:14
Last modified: 04 Jul 2022 18:14
Export record
Contributors
Author:
John Heaviside
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics