Effects of dimerization and interchain one-particle hopping in a weakly   coupled dimerized chain system at quarter filling
  Effects of the intrachain dimerization and the interchain one-particle hopping, $t_{b}$, in a quasi-one-dimensional dimerized chain system at quarter filling have been studied, based on the perturbative renormalization group (PRG) approach. Based on the results, we discuss difference in the low-energy properties between TMTTF and TMTSF compounds. 
Jun-ichiro Kishine and Kenji Yonemitsu (IMS)