Degree Type

Dissertation

Date of Award

1983

Degree Name

Doctor of Philosophy

Department

Chemistry

Abstract

Picosecond photophysical processes in 2- and 9-iodoanthracene in cyclohexane at room temperature were studied by triplet-triplet transient absorption spectroscopy between 420-500 nanometers. For small amounts of excess vibronic energy in S(,1), intersystem crossing from the first excited singlet state into high triplet states T(,n) (n > 1) with subsequent internal conversion to T(,1) or dissociation from the upper triplet manifold is suggested as a primary pathway for nonradiative relaxation. Rate constants for the processes were estimated using the results from previous fluorescence studies and the population risetime data for T(,1). Analyses of the photoproducts generated by excitation at two different wavelengths into the first excited singlet state reveal a vibronic level dependence of the photodissociation yield, indicating that photodissociation can proceed via at least two different mechanisms in the iodoanthracenes;Stimulated Raman processes and self-action effects are shownto be primarily responsible for the generation of a picosecondcontinuum when 532 nm picosecond pulses are focused into aCCl(,4) continuum cell. An experimental assessment of the artifactsintroduced by the angular distribution of continuum light on the;triplet-triplet absorption spectra of acridine is given and proceduresto minimize these effects are suggested; ('1)DOE Report IS-T-1042. This work was performed under contract number W-7405-Eng-82 with the U.S. Department of Energy.

DOI

https://doi.org/10.31274/rtd-180813-5994

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Cristiano G. Morgante

Language

en

Proquest ID

AAI8316330

File Format

application/pdf

File Size

205 pages

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