ESR investigations were performed for a series of organic conductors, (TMTTF)2X (X=SbF6, AsF6, PF6, ReO4, ClO4, SCN, Br). The ESR linewidth shows abrupt jumps or humps in the paramagnetic insulating region. The (TMTTF)2X compounds are roughly divided into three groups in the aspect of the anisotropy of the ESR linewidth at low-temperatures. We discuss the low-temperature charge distributed pattern from the microscopic point of view.
Nakamura, T. (2003). ESR investigation of charge localized states in (TMTTF)2X. In Synthetic Metals (Vol. 137, pp. 1181–1182). https://doi.org/10.1016/S0379-6779(02)01055-X