COOPERATIVE POLARIZATION IN ICE I-H AND THE UNUSUAL STRENGTH OF THE HYDROGEN-BOND

Cooperative polarisation in ice I-h is illustrated in clusters of eigh t molecules using local density functional calculations where the exch ange-correlation functional is a modified Ceperley-Alder expression. T hese parameter-free total energy calculations support the four-point c harge/polarisable point dipole model of Kozack and Jordan and indicate that cooperative polarisation has a profound effect, not simply incre asing the cohesive energy, but also making bond breaking disproportion ately difficult.