The location of the second critical point of water

Abstract

Based on the DTA data for homogeneous ice nucleation of emulsified liquid water at low temperatures and high pressures, the location of the second critical point (SCP) of water, which is expected to exist in addition to the normal liquid–vapor critical point, is estimated to be at 145 K < T c2 < 175 K and P c2 = ∼200 MPa ( T c2: second critical temperature, P c2: second critical pressure). It is shown that SCP is closely associated with the break point of the curve for the homogeneous ice nucleation temperature ( T H) of liquid water and with the transition between low density and high density amorphous solid water (LDA and HDA). Although the existence of SCP has become more realistic, the location seems to be less favorable to the water model of the second-critical-point interpretation.