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Vacuum-ultraviolet photoexcitation of some non-metal halides

Chim, Raymond Yin Loong (2003)
Ph.D. thesis, University of Birmingham.

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Abstract

The vacuum-ultraviolet (VUV) fluorescence spectroscopy of CX\(_2\)Y\(_2\) (X, Y = H, Cl or Br) has been studied following gaseous photoexcitation in the range 9-22 eV using synchrotron radiation. Fluorescence excitation, dispersed emission and action spectra have been recorded to probe the molecule in this way. Photoexcitation of these molecules has resulted in the population of Rydberg states of the neutral molecule and outer valence states of the parent ion. The study has shown that the emitters in the range 190-690 nm are due to either, neutral fragments formed by dissociation of Rydberg states of the neutral molecule or excited states of the parent ion. The identity of some of the dominant dissociation channels have also been identified via. appearance potentials extracted from action spectra. The threshold photoelectron photoion coincidence (TPEPICO) spectroscopy of CX\(_2\)Y\(_2^+\) (X, Y = H, Cl or Br), SeFe\(_6^+\), TeF\(_6^+\), SF\(_5\)CF\(_3^+\) and SF\(_5\)Cl\(^+\) has been studied following gaseous photoexcitation in the range ca. 12-27 eV using synchrotron radiation. The identity of some of the dominant dissociation channels have been identified in a similar way in which the information is extracted from action spectra in fluorescence spectroscopy. Appearance potentials extracted from ion yield plots have allowed comparison with known calculated thermochemistry. Measurement of fixed-energy TPEPICO spectra have been used to determine the decay dynamics of some two-bodied ionic dissociations. Finally, using a variation of TPEPICO spectroscopy, the kinetic energy released into certain fragments over a range of energies has been determined. Using an impulsive model, the data has been extrapolated to zero kinetic energy to obtain a value for the first dissociative ionisation energy of these molecules. From this value, more thermochemical data has been inferred.

Type of Work:Ph.D. thesis.
Supervisor(s):Tuckett, Richard Paul
School/Faculty:Schools (1998 to 2008) > School of Chemical Sciences
Department:School of Chemistry
Subjects:QD Chemistry
Institution:University of Birmingham
Library Catalogue:Check for printed version of this thesis
ID Code:1526
This unpublished thesis/dissertation is copyright of the author and/or third parties. The intellectual property rights of the author or third parties in respect of this work are as defined by The Copyright Designs and Patents Act 1988 or as modified by any successor legislation. Any use made of information contained in this thesis/dissertation must be in accordance with that legislation and must be properly acknowledged. Further distribution or reproduction in any format is prohibited without the permission of the copyright holder.
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