Figure 1. Comparison of the spectrum of the dipole time correlation function ◦calculated at 400◦C with the experimental IR spectrum. The experimental data in (a) by Tassaing et al. (Ref. 6) are taken at 380◦C with 0.009 g cm−3 and those by Vigasin et al. (Ref. 7) at 377◦C with 0.0105 g cm−3. In (b), the data by Tassaing et al. are at 380◦C with 0.04 g cm−3 and those by Vigasin et al. are at 377◦C with 0.0405 g cm−3. The calculated spectrum is shifted by 50 cm−1 to the higher frequency for comparison of the line shape to the experimental one.