The optical conductivity in spin density waves

We compute the optical conductivity perpendicular to the conducting chains in the spin density wave phase in Bechgaard salts (TMTSF)(2)X with X=PF6 and ClO4. We assume that the quasi-particle damping is entirely due to impurity scattering, and neglect the effect of imperfect nesting for simplicity. The present theory appears to describe the recent data from (TMTSF)(2)PF6 and (TMTSF)(2)ClO4 reasonably well.