Extended Data Fig. 9: Comparison of NNP-based 2D OH stretching vibrational modes in gas phase and frozen phonon liquid phase. | Nature

Extended Data Fig. 9: Comparison of NNP-based 2D OH stretching vibrational modes in gas phase and frozen phonon liquid phase.

From: Direct observation of ultrafast hydrogen bond strengthening in liquid water

Extended Data Fig. 9

a–h, The lowest vibrational eigenstates \(({n}_{1},{n}_{2})\)for a representative configuration (bond angle of 104.4°) among the 200 2D potential energy surfaces considered (a–c, e–g; dashed black lines indicate symmetric and antisymmetric displacements); and distribution of vibrational frequencies (defined as \(\varDelta {\nu }_{{n}_{1},{n}_{2}}={\nu }_{{n}_{1},{n}_{2}}-{\nu }_{0,0}\)) for the two lowest OH stretching vibrationally excited states for the 200 configurations (d, h). The distribution in the gas phase originates from the variation in the bond angle. The vertical lines indicate the experimental gas-phase stretch frequencies67 and \(\varDelta {\nu }_{1}\) from the 1D Lippincott–Schroeder model, respectively. i, Comparison of 1D OH stretch potentials for gas phase and liquid water as obtained from the NNP (blue and red, respectively) and the Lippincott–Schroeder model (black). The transparent thin lines correspond to the underlying 2 × 200 NNP replicates while the corresponding thick lines indicate the average potentials

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