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Spectroscopic properties of conjugated systems

The resonance energy transfer of electronic excitation between two weakly coupled molecules is discussed. The energy transfer mechanism between an isolated ground state acceptor and an excited sensitizer is studied in the dipole-dipole approximation , and the limitations of this model noted. Using the single acceptor-sensitizer pair interaction the behaviour, of a whole system of transferring species is investigated. A new cell-model is proposed for the statistical treatment of the transfer in solution and the results of a computer simulation of a random solution presented. The effect of diffusion on the transfer rate is also theoretically investigated. The time-dependent luminescence of a randomly distributed collection of sensitizer and acceptor molecules is discussed using a Green's function method when the exciting light is an arbitrary function of time . This theory is applied to the interpretation of phase-fluorimetry results. Theoretical expressions describing the effect of light attenuation in fluorescing solutions are given, and a model for secondary fluorescence and the trivial effect is proposed and tested against experimental results . An account of an apparatus for the observation and measurement of resonance energy transfer is given , and the results of an experimental investigation presented. The treatment of molecular π-electrons in the semi-empirical self-consistent field (SCF) approximation is discussed. A derivation of the Hartree-Fock SCF equations for both closed-shell ground states and half open-shell states is given. The nature and validity of the semi-empirical SOF approximation and the π-δ electron separability is considered. The Pople-Pariser-Parr approach is followed throughout.

Identiferoai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:623105
Date January 1968
CreatorsPacker, John Charles
PublisherImperial College London
Source SetsEthos UK
Detected LanguageEnglish
TypeElectronic Thesis or Dissertation
Sourcehttp://hdl.handle.net/10044/1/16026

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