The evaporation rate, free energy, and entropy of amorphous water at 150 K

Measurement of the rates of evaporation of amorphous water (a) and ice (i) near 150 K can be interpreted as giving a measure of their free energy difference, ΔaiG (150 K)=1100±100 J/mol, which, together with the known enthalpy difference and heat capacity data, suggests a residual entropy difference of ΔaiS (0)=−0.7±2.2 J/(K mol) at absolute zero. Previous theoretical estimates of ΔaiS (0), which are much larger, did not allow the amorph to be connected with normal liquid water by a reversible thermodynamic path at atmospheric pressure. The present value allows such a connection.