RESIDUAL ENTROPY OF ICE - A MANIFESTATION OF THE FRACTIONAL EXCLUSIONSTATISTICS IN REAL 3-DIMENSIONAL SPACE

We report here a tangible example of the fractional exclusion statisti cs in three spatial dimensions. We identify the chemical constraint of O-H bonds in ice, the so-called ice rule, as the origin of this novel statistics. Then the residual entropy of the crystalline ice is recog nized as arising from the fractional exclusion with the statistical in teraction parameter alpha = 0.867. Assuming the residual entropy of ic e reflects true accessibility to a macroscopic number of states throug h quantum tunnelling, we propose the possibility that Berry's phase su ppresses the tunnelling splitting of ground states and maintains the f inite residual entropy.