ADVANCED ELECTRON-PARAMAGNETIC-RESONANCE TECHNIQUES FOR THE STUDY OF COAL STRUCTURE

A combination of advanced transient electron paramagnetic resonance (e .p.r.) techniques have been applied to the study of the chemistry of c oals of widely varying rank. These pulsed e.p.r. experiments allow det ailed studies of the relaxation behaviour of the carbon radicals in co als, including the phase memory time (T(m)) and the electron spin latt ice relaxation time (T1e) which significantly augment the information obtained by conventional constant wave (c.w.) e.p.r. methods. Pulsed e lectron-nuclear double resonance allows quantitative determination of the various hyperfine interactions which the radicals have with proton s on the same and adjacent molecules. Another particularly striking ex tension of previous e.p.r. techniques is to use the dynamics of the el ectron spins to track the relaxation properties of protons in their vi cinity - the first instance of probing these nuclei which are inaccess ible by n.m.r. methods.