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Extension of principal component self-modeling analysis and conformational isomerism

Fluorescence and fluorescence-excitation spectra of trans-1-(2-naphthyl)-2-phenylethene (NPE), obtained under varying conditions of excitation and emission wavelengths, respectively, and oxygen concentration in methylcyclohexane are resolved into two distinct components by application of principal component analysis with self-modeling (PCA-SM). Resolved conformer fluorescence-excitation spectra are confirmed by use of an excitation-fluorescence/fluorescence two dimensional matrix. These spectra are used to decompose the UV absorption spectrum of NPE into conformer specific absorption spectra based on the assumption of excitation-wavelength independent fluorescence quantum yields for the individual conformers. / The first extension of PCA-SM to four component systems is presented. It is based on the assumption of minimum non-negativity of the spectral elements as given by Lawton and Sylvestre. Self-modeling curve resolution for a simulated four component system is accomplished by the projection of a 4-D tetrahedron in 4-D space to a 3-D tetrahedron in 3-D space. Explicit extension of the self-modeling technique to a four component case is described. Simulated data matrices having different S/N ranges as well as different spectral shapes and various spectral resolutions were employed to test the applicability of the method. / Fluorescence spectra of NPE obtained at different excitation wavelengths and tri-n-butylamine (TBA) concentrations (0.00 M-0.30 M) in methylcyclohexane were resolved into fluorescence spectra of the NPE conformers and of the two NPE-TBA exciplexes by use of principal component analysis combined with a four component self-modeling technique. Stern-Volmer constants, $K\sb{\rm svm},$ obtained from monomer fluorescence quenching and exciplex formation are 4.5 M$\sp{-1}$ and 24.66 $\pm$ 4.56 M$\sp{-1}$ for NPE$\sb1$ and NPE$\sb2,$ respectively. The fluorescence of the two exciplexes is quenched by TBA differentially with $K\sb{\rm sve2}$ = 0.85 $\pm$ 0.13 M$\sp{-1}$ and $K\sb{\rm sve1}$ is significantly larger than $K\sb{\rm sve2}.$ / Source: Dissertation Abstracts International, Volume: 53-11, Section: B, page: 5735. / Major Professor: Jack Saltiel. / Thesis (Ph.D.)--The Florida State University, 1992.

Identiferoai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_76807
ContributorsChoi, Jong-Oh., Florida State University
Source SetsFlorida State University
LanguageEnglish
Detected LanguageEnglish
TypeText
Format259 p.
RightsOn campus use only.
RelationDissertation Abstracts International

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