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Laser‐Excited Photothermal Lens Spectrometry in a Low‐Volume Cylindrical Sample Cell
Author(s) -
Bialkowski Stephen E.
Publication year - 1998
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.199800017
Subject(s) - photothermal spectroscopy , photothermal therapy , chemistry , irradiation , laser , ruthenium , analytical chemistry (journal) , excited state , photothermal effect , diffusion , spectroscopy , lens (geology) , optics , chromatography , atomic physics , biochemistry , physics , quantum mechanics , nuclear physics , thermodynamics , catalysis
A new apparatus for performing laser‐excited photothermal lens spectroscopy is described. The apparatus uses a sub‐microliter cylindrical sample cell, chopped laser excitation, and a continuous probe laser to perform photothermal lens spectrometry. The sample is irradiated with a constant irradiance beam, and the photothermal lens forms due to thermal diffusion through the sample cell walls. Solutions for the thermal diffusion equations predict a parabolic temperature change under continuous irradiation. Experimental results are obtained for organic and inorganic complexes in ethanol solution and compared to those obtained using a standard sample cell. Results for dicyclopentadienyl iron solutions excited with 10mW 514.5 nm Ar + laser radiation show that the cylindrical sample cell signal is 32% of that obtained using the standard sample cell. This ratio is in reasonable agreement with that expected based on thermal diffusion models. Results obtained for ruthenium tris‐bipyridyl chloride and perchlorate salts are not stable with respect to irradiation time. The latter results suggest that a significant amount of ruthenium tris‐bipyridyl complex is photolyzed with the mild irradiation conditions used in these experiments.