Fig. 4.

²H solid-state NMR spectra of deuterated Himd⁺ cations at various temperatures. The black and red lines represent the experimental spectra and the simulation results, respectively. According to the simulation results, the ²H pattern at each temperature can be deconvoluted into two components with an intensity ratio of 6:4. The motions 1 (purple line) and 2 (green line) should correspond to the different dynamic modes of the Himd⁺ cations in layers A and B, respectively. The molecular structure depicts the thermodynamic motion of Himd⁺, where μ is the mean amplitude of the in-plane wobbling angle around molecular C₅-axis and σ is the out-of-plane vibration angle