English: The time-evolution of the Koopman-von Neumann classical wave function for the Morse potential: ${\displaystyle U(x)=20(1-<!--\; -\; -->e^{-<!--\; -\; -->0.16x}{)}^2}$ in atomic units (a.u.). Black dots are classical particles following the corresponding Newton's law of motion. The solid lines represent the level set of the Hamiltonian ${\displaystyle H(x,p)=p^2/2+U(x)}$.