Ellipsometry of the electrified interface
Ellipsometry of the electrified interface
Use has been made of an automatic nulling ellipsometer, capable of monitoring changes in the polarisation state of reflected light with high sensitivity and speed, to study several aspects of ionic and organic adsorption at the mercury and platinum-aqueous electrolyte interfaces. The ellipsometer was used to monitor, continuously, the changes of the optical parameters, A and w, as a function of electrode potential in studies of ionic adsorption and the adsorption of organic materials onto mercury. The method of computerised data acquisition employed enabled the optical studies of adsorption to be extended by using a wide range of wavelengths in the visible to near ultra-violet spectral region. This additional wavelength information has clearly shown the inadequacy of macroscopic models used to describe ionic adsorption. For dilute solutions of isoquinoline, the potential dependent changes in w were complicated by effects other than simple changes in inner layer refractive index. For more concentrated solutions the changes in both a and y were satisfactorily accounted for by an adsorbed layer exhibiting uniaxial anisotropy. Analysis of the data collected for different wavelengths gave similar results, after allowing for normal dispersion of the inner layer refractive index, which are in agreement with the recently proposed model for this system. The optical properties of rhodamine B adsorbed on mercury have been determined by in situ spectroscopic ellipsometry. After correcting the experimental A,W dispersion curves for the effects of an absorbing medium the optical constants of the adsorbed layer were found for all wavelengths in the range 300 nm to 650 nm. The extinction coefficient of the adsorbed dye showed a red shift of about 60 nm together with a weakening of the extinction compared to that of the bulk solid dye. Analysis of the data obtained for the adsorption of rhodamine B onto platinum failed to yield reasonable film optical properties. The strong similarity between the A dispersion curves for the two substrates suggests that the properties of the adsorbed layer on platinum are similarly shifted.
University of Southampton
Pearson, Peter John
dbc67d91-2429-4553-a9f0-8a25f93513a2
March 1983
Pearson, Peter John
dbc67d91-2429-4553-a9f0-8a25f93513a2
Pearson, Peter John
(1983)
Ellipsometry of the electrified interface.
University of Southampton, Doctoral Thesis, 221pp.
Record type:
Thesis
(Doctoral)
Abstract
Use has been made of an automatic nulling ellipsometer, capable of monitoring changes in the polarisation state of reflected light with high sensitivity and speed, to study several aspects of ionic and organic adsorption at the mercury and platinum-aqueous electrolyte interfaces. The ellipsometer was used to monitor, continuously, the changes of the optical parameters, A and w, as a function of electrode potential in studies of ionic adsorption and the adsorption of organic materials onto mercury. The method of computerised data acquisition employed enabled the optical studies of adsorption to be extended by using a wide range of wavelengths in the visible to near ultra-violet spectral region. This additional wavelength information has clearly shown the inadequacy of macroscopic models used to describe ionic adsorption. For dilute solutions of isoquinoline, the potential dependent changes in w were complicated by effects other than simple changes in inner layer refractive index. For more concentrated solutions the changes in both a and y were satisfactorily accounted for by an adsorbed layer exhibiting uniaxial anisotropy. Analysis of the data collected for different wavelengths gave similar results, after allowing for normal dispersion of the inner layer refractive index, which are in agreement with the recently proposed model for this system. The optical properties of rhodamine B adsorbed on mercury have been determined by in situ spectroscopic ellipsometry. After correcting the experimental A,W dispersion curves for the effects of an absorbing medium the optical constants of the adsorbed layer were found for all wavelengths in the range 300 nm to 650 nm. The extinction coefficient of the adsorbed dye showed a red shift of about 60 nm together with a weakening of the extinction compared to that of the bulk solid dye. Analysis of the data obtained for the adsorption of rhodamine B onto platinum failed to yield reasonable film optical properties. The strong similarity between the A dispersion curves for the two substrates suggests that the properties of the adsorbed layer on platinum are similarly shifted.
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83131961
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Published date: March 1983
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Local EPrints ID: 459730
URI: http://eprints.soton.ac.uk/id/eprint/459730
PURE UUID: 24bef028-5cac-4217-aa77-f3c5812386fb
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Date deposited: 04 Jul 2022 17:17
Last modified: 16 Mar 2024 18:32
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Author:
Peter John Pearson
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