“…For example, ρ of (TMTTF) 2 AsF 6 , which exhibits sP transition at 14 K, is estimated to 0.21e and 0.16e by infrared spectroscopy of two groups, 11,12 0.50e and 0.33e, which are estimated values at lowest temperature from the temperature-dependent ratio of spin-lattice relaxation rate T −1 1 , by the NMR measurements of two groups. 13,14 It should be also noted that a slight decrease 11 or the constant value 12 of ρ is reported when it enters the sP state, whereas the NMR study suggested that the charge separation is diminished in the sP phase. 14 In the (TMTTF) 2 SbF 6 salt, ρ is estimated to 0.29e, which is almost temperature independent, by infrared spectroscopy, 15 0.50e, and 0.55e by the NMR T −1 1 measurements of two groups.…”