The Peierls transition of Perylene radical cation salts with 2:1 stoichiometry containing tetrahydrofuran

Peierls Instability and Charge-Density-Wave Transport in Fluoranthene and Perylene Radical Cation Salts

“…The step-like increase in conductivity shows that the systems investigated react very sensitively on a change in the molecular orbital overlap. These phase transitions are also seen in other experiments like differential scanning calorimetry, static magnetic susceptibility and microwave conductivity [8]. Especially the temperature dependence of the microwave conductivity measured at 10.2 GHz shows the same behaviour as the dc conductivity in the temperature range from room temperature to 50 K. This indicates that the observed effects are not due to the influence of contacts (mechanical stress), which can sometimes be a source of artefacts (resistivity jumps) in organic conductors.…”

“…At the 220 K phase transition the slope of σ(T) changes and at 155 K a sudden increase in conductivity is observed. From crystal structure and ESR measurements it is supposed that the phase transition at 220 K is due to an ordering process in the solvent molecules and the one at 155 K due to a slight rotation of neighbouring perylene molecules in the conducting stack [8]. The step-like increase in conductivity shows that the systems investigated react very sensitively on a change in the molecular orbital overlap.…”

ESR Imaging of Conduction Electrons in Organic Conductors

“…The measurements at X‐band were performed at 230 K after 10 months' storage of the crystal at 255 K in a freezer. (2D projection reconstruction, converted to Cartesian coordinates, pixel size 24 × 24 m̈m 2 .) Spin density and T 2 ‐distributions could be compared before and after aging 13 .…”

“…The absolute value and the anisotropy of the conduction electron spin diffusion coefficient D depends on the defect content of the individual rcs single crystal as well as on the spatial distribution of the defects. Typical values of the conduction electron mobility are 50 cm 2 /Vs at 250 K. Free diffusion from one end of a crystal to the other (∼1 mm) has been observed for some (FA) 2 PF 6 crystals 9 . Most generally, however, diffusion is restricted with a characteristic length of the chain length distribution of about 100 m̈m 10 .…”

“…13 The characteristic angle of 104° between the a axis and the c stacking axis of the FA molecules can be seen at the right end. Cross section 0.2 × 0.5 mm 2 .…”