Extended Data Fig. 2: Wigner sampling.
From: Direct observation of ultrafast hydrogen bond strengthening in liquid water
a, The three lowest eigenstates (coloured lines) and eigenvalues (horizontal grey lines) of the Lippincott–Schroeder model potential (black line). Inset, the probability distribution of the vOH = 0 and vOH = 1 states, μ and σ represent mean and standard deviation. b, c, Wigner distribution for vOH = 0 (b) and vOH = 1 (c). The region of phase space with negative values of the vOH = 1 distribution (orange shades) was excluded from the sampling. Note the different colour gradient used for negative function values. Lippincott–Schroeder model (ROO = 2.85 Å) is used for sampling of the initial displacements and velocities along the OH bonds of the excited molecules
