Figure 6
Vibrational modes given as ν6–ν9 in Fig. 5 (τ: torsion). The frequency of each mode is the result calculated with a dielectric constant of 4.20. The blue arrows indicate the atomic displacement vectors. Intramolecular hydrogen bonds are indicated by the dashed lines, and the orange dashed line is the hydrogen bond HB4 given in Fig. 4a. The red circle represents the two atoms that form the torsion axis, and the movement around the torsion axis is indicated by the red arrows.
