||In this course, it is proposed to give a good foundation to the underlying principles and simple applications of Electron Paramagnetic Resonance (EPR) Spectroscopy, along with a detailed exposition of the EPR spectrometer and how to record and analyze simple EPR spectra. First a short historical development will be given which encompasses the discovery the Zeeman effect, the existence of electron spin and Zavoisky’s observation of electron spin resonance. The hurdles and hostilities that these pioneers faced will be mentioned. Then the phenomenon of magnetic resonance will be discussed in terms of classical mechanics and quantum mechanics. The necessary conditions for experimental observation of the resonance will be elucidated and the experimental techniques will be elaborated. Often the approach will be that of an experimentalist, so that the necessary theoretical concepts will be built from experimentally observed features, and not the other way round. A good part will be devoted to a detailed description of EPR instrumentations, so that one clearly understands how the principles of EPR spectroscopy are implemented in the spectrometers, and also the methods to enhance their sensitivity. A detailed guided tour will be conducted explaining how to record the best quality EPR spectra, and how to analyze first-order EPR spectra. EPR study of free radicals, especially organic, has yielded much valuable information, and these will be highlighted. Some emphasis will be placed on EPR studies related to photochemical reactions. This will include the means of recording EPR spectra of transient radicals through steady-state and time-resolved techniques and the spin trapping technique. The phenomenon of Electron Spin Polarisation (ESP), the more modern term of Chemically Induced Dynamic Magnetic Polarization, will be explained, and special EPR instrumentation to detect it will be described. Then a general outline of the importance of electron spin relaxation on the magnetic resonance spectroscopy will be given, the Bloch equations will be introduced and their significance in the EPR lineshapes will be highlighted.
Throughout this course, the emphasis will be on building a physical picture, with minimum use of the mathematical rigour.