Investigations of the triplet states of 1-phenyl-2-(2-naphtyl) ethylene (2-NPE), under steady-state conditions in the presence of competing energy-transfer and spin-exchange quenchers have allowed obtention of effective triplet lifetimes, and decay parameters. Direct transient observations, done in collaboration with H. Gorner, have confirmed the steady-state results, as well as defined triplet state parameters for two distinct 2-NPE species. Investigations of both types on conformationally restricted analogs, representative of conformers formed by 1-(alpha) rotation of the 2-naphthyl moiety, have confirmed the identification of the two 2-NPE species as conformational isomers. / Studies in the excited singlet manifold have focused on separation and independent treatment of the properties of the multiple emissive 2-NPE species. Observations of fluorescence spectra under conditions of variable excitation wavelength, temperature, viscosity, and added singlet state quenchers were performed and quantitated in terms of component contributions by application of Principal Component Analysis (PCOMP); which determines the number of significant contributing species, their intrinsic spectra, and their relative amounts without any prior knowledge of component properties. Again, similar studies performed on the conformationally defined analogs, have indicated their similarity to the 2-NPE species observed and indicate their formation via the proposed ground state conformational equilibrium. Aside from confirming the previously proposed ground state conformational control of excited state behavior, the detailed analysis strongly suggests the dynamic involvement of allowed and forbidden pairs of states within each excited conformer. / In addition, photochemical investigations of all substrates in both the singlet and triplet manifold have provided evidence for direct cis-trans isomerization via the excited singlet, as well as exhibiting behavior in many respects similar the the symmetrical homolog, stilbene. In all cases, correlation of 2-NPE comformer behavior to that of the analogs has been successful, and suggests a direct effect of single-bond rotation in determining excited state properties. Analysis of this effect in terms of excited transitions and energetics is proposed to account for the observations. / Source: Dissertation Abstracts International, Volume: 45-04, Section: B, page: 1194. / Thesis (Ph.D.)--The Florida State University, 1984.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_75317 |
| Contributors | EAKER, DAVID WILLIAM., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 554 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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