ABSTRACT
This chapter demonstrates the advantages of 2-mm Electron Paramagnetic Resonance (EPR) spectroscopy in the study of various condensed systems. The most effective and widely used method to study molecular mobility in condensed systems is the EPR method, which gives significant information on the motion of radical centers or spin-labeled segment of a macromolecule. The structural and dynamics investigation of the condensed systems are most commonly carried out at 3-cm wave band EPR. However, the EPR spectra of organic free radicals, including nitroxide radicals, are registered in a narrow range of magnetic fields at this wave band. A high spectral resolution of 2-mm EPR spectroscopy plays a dominating role also in the investigation of molecular dynamics in condensed systems due to the possibility of a separate registration of lines, corresponding to g-tensor canonic values, and consequently of their shape changes, stipulated by molecular motion of each of them.
