The lasing characteristics and the spectroscopy of intramolecular proton transfer molecules have been investigated in nonpolar and polar solvents. In addition molecular orbital calculations on intramolecular proton transfer molecules have been performed. The efficient generation of coherent stimulated emission from 3-hydroxyflavone (3-HF) and fisetin, two molecules which exhibit intramolecular proton transfer has been shown. Amplified spontaneous emission from 3-HF is achieved in polar aprotic and moderately protic solvents. The observed shifts of the tautomer fluorescence are attributed to hydrogen bonding interactions with the solvent. In contrast 3-hydroxychromone does not exhibit amplified spontaneous emission in various solvents and concentrations. Picosecond transient absorption experiments reveal the existence of absorption bands overlapping the emission, which leads to high loss terms in the gain equation. The extensive aggregation of this molecule at high concentrations further lowers the gain coefficient for stimulated emission. 3-HF has been shown to form the anion in the ground state in formamide solutions. The distinct absorption, emission and transient absorption bands of the anion have been identified. The transient absorption bands of the neutral molecule are not affected by the polar environment. The risetime of the tautomer fluorescence is shown to be slowed by hydrogen bonding interference from the solvent. Ab initio calculations on 3-hydoxy-4-pyrone predict the possibility of intramolecular proton transfer in the excited state. The dipole moment values and the Mulliken population analysis are consistent with the proton transfer picture. INDO calculations on the same molecule show a discrepancy with the ab initio results. Benzanilide shows a very fast monoexponential rise of the tautomer fluorescence at room temperature. At 77 K the rise / becomes biexponential. The tautomer ground state transient absorption has been observed. The results are explained in terms of a double proton transfer mechanism resulting from dimer formation. Finally a supersonic molecular beam apparatus is described. / Source: Dissertation Abstracts International, Volume: 49-07, Section: B, page: 2671. / Major Professor: Michael Kasha. / Thesis (Ph.D.)--The Florida State University, 1988.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77813 |
| Contributors | Parthenopoulos, Dimitrios Alfred., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 244 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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