Fig. 3: Activation barrier and reorientational dynamics of NPG.
From: Understanding colossal barocaloric effects in plastic crystals
Calculated activation energy barrier of rotating of (a) CH3 group, (b) CH2OH group, and (c) the entire NPG molecule in both monoclinic and cubic phases. d Pressure-dependent activation energy barrier of the rotating CH3 group and the entire NPG molecule. e Inelastic neutron-scattering profiles as a function of energy transfer E at 1.65 Å−1 ≤ Q ≤ 1.75 Å−1 at temperature 320 K. The experimental data were reproduced based on a combination of a constant background (BKG), a resolution-convoluted delta function (elastic), and two Lorentzian functions (L1 and L2). f Calculated temperature dependence of rotating rate (in log scale) for the NPG molecule in monoclinic and cubic phases. Green star indicates their corresponding experimental values obtained from neutron-scattering data at different temperatures above Tc, as shown in Supplementary Fig. 2a, b. The two lines at each phase show the value by changing attempt frequency; gray dash lines are guided for your eyes. The simulated temperature is from 100 to 500 K, and the vertical blue line indicates the critical temperature of phase transition.
