  We propose a simple cluster-based method with application to calculations of
Compton profile anisotropies of ice. The convergence of the method is checked
with respect to Crystal95 results. Increasing both basis-set quality and
cluster sizes results in a decrease of the magnitude of theoretical Compton
anisotropies. The agreement with experimental data is therefore improved
towards previously calculated anisotropies. Moreover, analyzing directional
autocorrelation functions shows an evidence for both anti-bonding and
polarization effects.
