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Resolving Component Overlap in Multiwavelength Kinetic Spectroscopy: Application to Raman Scattering from Intermediates in Triplet‐State Photoreactions
Author(s) -
Fister Julius C.,
Harris Joel M.
Publication year - 1997
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1997.tb01876.x
Subject(s) - component (thermodynamics) , kinetic energy , spectroscopy , raman spectroscopy , photochemistry , triplet state , raman scattering , chemistry , materials science , molecular physics , physics , optics , molecule , thermodynamics , organic chemistry , quantum mechanics
— Understanding of reaction mechanisms in photochemistry is advanced both by kinetic measurements to determine rates of reaction and by spectroscopic studies of the structures of precursors and photoproducts. When kinetics and spectroscopy are combined in a time‐resolved, multiwavelength spectroscopic measurement on a reacting system, spectra and structures of intermediates can also be determined. In this paper, the application of multidimensional least‐squares and factor analysis techniques for resolving overlapped spectra from intermediates in photochemical kinetics are discussed. The methods are employed specifically to resolve Raman spectra of intermediates in triplet‐state photoreactions. By varying excitation intensity, spectra of excited‐triplet states are resolved from ground states and solvent. By varying the concentration of a triplet quencher in the sample, the Raman spectrum of a sensitizer excited state (benzophe‐none) can be resolved from those of acceptor‐triplet states or radical photoproducts. Applications of these concepts in other areas of photochemical kinetics are addressed.