X-ray diffuse scattering study of the organic one-dimensional conductor TMTTF-bromanil

In the title compound, both 2kF and 4kF incommensurate lattice modulations were found by diffuse x-ray scattering. 4kF streaks are observed already at room temperature, below which the dc conductivity shows non-metallic behavior, but they do not turn into satellite spots at low temperatures. 2kF broad spots develop rapidly below about 80K, temperature below which the spin susceptibility vanishes and the electrical conductivity decreases more rapidly. It is suggested that the system may have a character intermediate between the Peierls and the spin-Peierls transitions. © 1983.