Physical properties and the Peierls instability of ${\mathrm{Li}}_{0.82}$[Pt${\left({\mathrm{S}}_2{\mathrm{C}}_2{\mathrm{}\left(\mathrm{CN}\right)\mathrm{}}_2\right)}_2$] · 2${\mathrm{H}}_2$O

The infrared reflectivity, the temperature-dependent conductivity, and thermopower of the one-dimensional conductor ${\mathrm{Li}}_{0.82}$[Pt${\left({\mathrm{S}}_2{\mathrm{C}}_2{\mathrm{}\left(\mathrm{CN}\right)\mathrm{}}_2\right)}_2$] · 2${\mathrm{H}}_2$O, LiPt(mnt), is presented. It undergoes a simple Peierls transition at $T_c=215\mathrm{}$ K, which is not influenced by correlations or by cation ordering. The metallic LiPt(mnt) is characterized by a transfer integral $\left|t_{\parallel }\right|\approx 0.1$ eV. When $155 \mathrm{K}<T<\mathrm{}{T}_c$ it behaves as an intrinsic Peierls semiconductor with $\Delta \approx 36$ meV. At lower temperatures the thermopower indicates extrinsic behavior due to the presence of donor impurities. Our results agree with those obtained from magnetic-susceptibility studies.