  To comprehend the complexities of the ice-water interface, we perform a study
that attempts to correlate the altered dynamics of water to its perturbed
structure at, and due to, the interface. The deviation from bulk values of
structural and dynamical quantities at the interface are obtained by computer
simulations. Water molecules are found to get exchanged between the ice-like
and water-like domains of the interface with a time scale of the order of ~10
ps. To investigate the effect of interfaces in general, we study three other
systems, namely (i) water between two hydrophobic nano-slabs, (ii) water at
protein and (iii) DNA surfaces. In all these systems, we find that the
difference from bulk properties become negligible beyond ~1 nm, with structural
features converging to bulk values faster than the dynamical properties. Even
in the case of the latter, we find that single-particle and collective
properties behave differently. The approach to bulk values is rapid except for
collective shell-dipole moments. We present a new insightful characterization
of the surfaces by establishing a quantitative correlation between
tetrahedrality order parameter (q_td) and dynamics by diffusion (D) and angular
jumps. In the ice-water system, we find that the variation of qtd, as we move
from solid to the liquid phase, correlated well with D. The correlation is
found to be present in all the interfaces studied. Our results can be used to
explain the experimental outcomes of the likes of dielectric relaxation and
solvation dynamics.
