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|Title:||Electronic spectroscopy of some metal-containing free-radicals|
|Authors:||Pooley, Simon Jonathan.|
|Presented at:||University of Leicester|
|Abstract:||Laser-induced fluorescence (LIF) spectroscopy has been used to probe the properties of some metal-containing free-radicals. These radicals were formed using three different techniques; fragmentation through electric discharge, laser ablation and laser photolysis and were studied in a supersonic jet expansion.;A dispersed fluorescence spectroscopic study of the zinc-monoethyl free radical was performed. From this work vibrational frequencies, particularly of the Zn-C stretching and the Zn-C-C bending modes, have determined for both the XËœ and A states. In addition several peaks in the excitation spectrum reported by Povey et al. (22500--24000 cm-1) have been assigned.;Recently Professor T.A. Miller and co-workers at Ohio State University recorded rotationally-resolved LIF spectra of ZnC2H5 in the 22500--23100 cm-1 region. This study complemented the dispersed fluorescence work described above, so the author was asked to generate a model and interpret this spectra.;A Hamiltonian model to simulate rotational structure of asymmetric top molecules which includes spin-rotation terms has been written by the author to form part of a spectral simulation program. This program was used to simulate the rotationally resolved LIF spectra of ZnC2H5 detailed above. Unfortunately a complete analysis has not been possible but values for the A, B and C rotational constants for many of the bands are presented here along with a analysis of the observed values of spin-rotation constants.;Finally, LIF spectra of a new electronic transition of BaOH, the DËœ2sum+ - X 2sum+ system has been observed. Also, the CËœ - XËœ system was reinvestigated. The CËœ - XËœ system is particularly interesting because it shows much more complexity than might be expected from previous studies. Vibrationally and partially rotationally resolved spectra are reported for both systems and the CËœ - XËœ region offers some evidence that the molecule may be bent in the excited state with a large spin-rotation interaction coupling.|
|Rights:||Copyright © the author. All rights reserved.|
|Appears in Collections:||Theses, Dept. of Chemistry|
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