Capturing Individual Hydrogen Bond Strengths in Ices via Periodic Local Vibrational Mode Theory: Beyond the Lattice Energy Picture

Local
stretching force constants derived from periodic local vibrational
modes at the vdW-DF2 density functional level have been employed to
quantify the intrinsic hydrogen bond strength of 16 ice polymorphs,
ices Ih, II, III, IV, V, VI, VII, VIII, IX, XI, XII,
XIII, XIV, XV, XVII, and XIX, that are stable under ambient to elevated
pressures. Based on this characterization on 1820 hydrogen bonds,
relationships between local stretching force constants and structural
parameters such as hydrogen bond length and angle were identified.
Moreover, different bond strength distributions, from uniform to inhomogeneous,
were observed for the 16 ices and could be explained in relation to
different local structural elements within ices, that is, rings, that
consist of different hydrogen bond types. In addition, criteria for
the classification of hydrogen bonds as strong, intermediate, and
weak were introduced. The latter was used to explore a different dimension
of the water–ice phase diagram. These findings will provide
important guidelines for assessing the credibility of new ice structures.