Electron spin resonance classification

We report an electron spin resonance (ESR) study on a C60 anion and a metal (M) encapsulated in fullerene (C ) (a metallofullerene M C ). The anisotropy components of the g-factor of Cg0 were determined accurately from the analysis of angular-dependent ESR spectra of single crystal Cg0 salt. The evaluation of the g-factor was performed according to the classification of symmetry of the C60 geometry. It was found out from the evaluation that the molecular structure of Cg0 should he distorted to lower symmetry, C2h or C,. The variety of ESR spectra of metallofullerenes of La C s was obtained in terms of a g-factor, a hyperfine coupling constant, and a line width. In the case of the isomer I of La C80 and the isomer II of La C84, an abnormally large line width was measured. The molecular structure with high symmetry would reflect on the specific spin dynamics. 

Examples of this type of classification for anodic and cathodic processes are given in the two schemes shown below as Figures 2 and 3. In some cases, the existence of the radical ions involved and their nature has been proved by means of electron spin resonance spectroscopy. 

Taking a different route to materials characterization, Hayes and Schurr use an experimental archaeological approach to develop a method for classification of archaeological maize and bone. They prepare comparative sets of maize and bone heated to different temperatures for differing periods of time and in conditions that include or exclude oxygen. Using Electron Spin Resonance (ESR), they are able to determine the maximum heating temperature... 

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