  Combining the Lagrangian-Laplace mechanics and the known pressure dependence
of the length-stiffness relaxation dynamics, we have determined the critical,
yet often-overlooked, short-range interactions in the hydrogen bond of
compressed ice. This approach has enabled determination of the force constant,
cohesive energy, potential energy of the vdW and the covalent segment at each
quasi-equilibrium state as well as their pressure dependence. Evidencing the
essentiality of the inter-electron-pair Coulomb repulsion and the segmental
strength disparity in determining the asymmetric H-bond relaxation dynamics and
the anomalous properties of ice, results confirmed that compression shortens
and stiffens the OH bond and meanwhile lengthens and softens the covalent bond.
