X-ray investigation of the tetramethyldithiadiselenafulvalene (TMDTDSF)2X series of organic conductors. I. Study of the orientational disorder of the TMDTDSF molecule Q. Liu, S. Ravy, J. P. Pouget, I. Johannsen et K. BechgaardJ. Phys. I France, 3 3 (1993) 803-819DOI: https://doi.org/10.1051/jp1:1993164