Kinetic energy density inside the core for the m = 0 libration forcing as a function of (a) the forcing frequency ω for different profiles of the Brunt–Väisälä frequency at the CMB and (b) the Brunt–Väisälä frequency N ₀ at the peak forcing frequency ω = 0.6576 (denoted by the dashed–dotted vertical line). The solid vertical line coincides with the observed libration frequency ω = 0.67 in Mercury, and the remaining model parameters are E = 10⁻⁸, r _C = 0.7, h = 0.1, and r _ICB = 0.4.