Figure 3.

Overlay of the FT-IR absorption spectra of TTF-CAH2 at 300 K (dark red), 250 K (light red), 200 K (orange), 150 K (brown), 100 K (green), 50 K (light blue), and 10 K (dark blue), for (a) TTF-CAH2 form I, and (b) TTF-CAH2 form II. The band gaps shown in the figure correspond to the absorption edges, estimated as the extrapolation of the dashed lines on the frequency axes at 1175 cm−1 for form I and 925 cm−1 for form II, respectively.