Negative thermal expansivity of ice: comparison of the monatomic mw model with the all-atom TIP4P/2005 water model

Abstract

We calculate the thermal expansivity of ice I for the monatomic mW model using the quasi-harmonic approximation. It is found that the original mW model is unable to reproduce the negative thermal expansivity experimentally observed at low temperatures. A simple prescription is proposed to recover the negative thermal expansion by re-adjusting the so-called tetrahedrality parameter, _. We investigate the relation between the _ value and the Grüneisen parameter to explain the origin of negative thermal expansion in the mW model and compare it with an all-atom water model that allows the examination of the e ect of the rotational motions on the volume of ice.