Conductivity mode in blue bronze.

Far-infrared reflectance measurements down to 4 cm(-1) are presented for K(0.3) MoO(3) at 2K. The complex conductivity can then be calculated via Kramers-Kronig transformations. Together with micro-wave measurements, the real part of the conductivity shows a peak at ~=2.8cm(-1). This is interpreted as due to a pinned charged density wave. The pinned frequency is in the same frequency range as other inorganic quasi-1-dimensional materials, NbSe(3) and TaS(3). We find the effective mass to be 10(4) m(e) and the damping frequency to be ~=5.5cm(-1) (175 GHz).