A comparison of the numerical anharmonic vibrational wavefunction with that from the harmonic approximation is shown in Figure . The asymmetry of the anharmonic potential with respect to the equilibrium geometry r e leads to the shift of the probability distribution into the range of larger interatomic distances r. Wigner distribution at ) for the ground vibrational state of the molecular cation H + 2 . Horizontal lines show the results of the harmonic (h, black line), anharmonic (anh, blue line), and MD with WS ("WS+MD", red line). The curves show results of the MBS+MD and SWS+MD simulations at different τ = h/(k B T ).