Triplet spin excitons, structure and conductivity of (TMN)3(AsF 6)2 and (TMN)3(ClO4)2 , the radical cation salts of tetramethoxynaphthalene

Open Access
Publisher Website
Google Scholar
Abstract
The 3 : 2 stoichiometry of the (TMN)3(AsF6) 2 salt is reflected in an alternating stack configuration with TMN-triads resulting in a diamagnetic ground state. Triplet spin excitons are accessible with activation energies of 0.19 eV (AsF6) and 0.28 eV (ClO 4). The respective fine structure parameters are D = ± 0.00667 cm -1, E = ∓ 0.00117 cm-1 and D = ± 0.00829 cm -1, E = ∓ 0.00090 cm-1. Spin exchange leads to line narrowing at higher temperatures. The conductivity is quite low (δ(300 K) ∼ 10-4Ω-1 cm-1 (TMN)3(AsF 6)2) and may result from charge carriers, thermally activated from defect states and across the band gap, respectively