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Picosecond spectroscopy of reactive intermediates: Generation and dynamics of arylmethyl ions and radicals in solution

A detailed experimental description is presented of a practical and relatively inexpensive approach for two simultaneous and independent types of picosecond spectroscopic measurements. Two data collection subsystems, (1) a picosecond pump-probe transient absorption/emission spectrometer and (2) a streak camera system for time-dependent measurements of absorption and emission, were developed as independent subsystems within an integrated system based on a single mode-locked Nd:YAG laser which concurrently supplies each subsystem with picosecond pulses. Considerations concerning electrical and optical interfacing between the two subsystems are discussed. / With these two subsystems, picosecond-pulsed photolyses of diphenylmethyl chloride, diphenylmethyl bromide, triphenylmethyl chloride, triphenylmethyl bromide, and triphenylacetyl chloride in acetonitrile, methylene chloride, and cyclohexane were studied. The dependence of the yields of radicals and ions are discussed with respect to the nature of the starting compound and the solvent. Ion-pair dynamics were monitored with subsystems 1 and 2. Microscopic rate constants for the collapse of the contact ion pair (CIP), separation of the CIP, and reformation of the CIP from the separated ions were calculated. / The photophysics and photochemistry of the triphenylmethyl radical generated from triphenylmethyl chloride, and triphenylacetyl chloride, and tert-butyl triphenylperacetate in solution were studied by means of a unique three-pulse picosecond transient absorption technique. The emission lifetime of the excited triphenylmethyl radical was measured as a function of solvent polarity with subsystem 2. These data were collectively used to gain an understanding of the electronically excited triphenylmethyl radical. / Source: Dissertation Abstracts International, Volume: 50-03, Section: B, page: 0980. / Major Professor: Edwin F. Hilinski. / Thesis (Ph.D.)--The Florida State University, 1989.

Identiferoai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_77990
ContributorsSchmidt, Jeffrey Allan., Florida State University
Source SetsFlorida State University
LanguageEnglish
Detected LanguageEnglish
TypeText
Format271 p.
RightsOn campus use only.
RelationDissertation Abstracts International

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