Keele Research Repository

The work described in this thesis is concerned with the development of millimeter wave electron spin resonance spectrometers, and the application of such spectrometers to a study of the ferric ion in myoglobin.
Firstly an outline of the basic theory and techniques of electron spin resonance is given, along, with a discussion of the theoretical sensitivity of E.S.R. spectrometers. The basic techniques applicable to the design of millimeter wave spectrometers are then reviewed, with particular reference to those which are significantly different to conventional microwave techniques.
A review of the basic theory of the paramagnetic ion in a crystal lattice is given in Chapter III, followed by a discussion of the properties of myoglobin. In these two chapters the basic equations needed for the interpretation of tile results obtained are set up.
A detailed description of the 4mm and 2mm spectrometers is given in Chapter VI, together with descriptions of the fabrication of components, and of the superconducting magnet. The sensitivity of the 4mm spectrometer was found to be 2 x 10 10 spins per unit linewidth for an integrating time of 1sec. This figure compares favourably with the maximum theoretical sensitivity of 4.3 x 10 9 spins.
The final chapter describes measurements at 4mm on acid met myoglobin both in paste and single crystal form. The results are interpreted in terms of an effective Spin Hamiltonian and the parameters of this Hamiltonian have been derived from the experimental results.